962 sp chemistry

STPM/S(E)962

PEPERIKSAAN

SIJIL TINGGI PERSEKOLAHAN MALAYSIA (MALAYSIA HIGHER SCHOOL CERTIFICATE EXAMINATION)

CHEMISTRY Syllabus, Specimen Papers and Specimen Experiment

This syllabus applies for the 2012/2013 session and thereafter until further notice.

MAJLIS PEPERIKSAAN MALAYSIA (MALAYSIAN EXAMINATIONS COUNCIL)

FALSAFAH PENDIDIKAN KEBANGSAAN

“Pendidikan di Malaysia adalah satu usaha berterusan ke arah memperkembangkan lagi potensi individu secara menyeluruh dan bersepadu untuk mewujudkan insan yang seimbang dan harmonis dari segi intelek, rohani, emosi, dan jasmani. Usaha ini adalah bagi melahirkan rakyat Malaysia yang berilmu pengetahuan, berakhlak mulia, bertanggungjawab, berketerampilan, dan berkeupayaan mencapai kesejahteraan diri serta memberi sumbangan terhadap keharmonian dan kemakmuran keluarga, masyarakat dan negara.”

FOREWORD This revised Chemistry syllabus is designed to replace the existing syllabus which has been in use since the 2001 STPM examination. This new syllabus will be enforced in 2012 and the first examination will also be held the same year. The revision of the syllabus takes into account the changes made by the Malaysian Examinations Council (MEC) to the existing STPM examination. Through the new system, sixth-form study will be divided into three terms, and candidates will sit for an examination at the end of each term. The new syllabus fulfils the requirements of this new system. The main objective of introducing the new examination system is to enhance the teaching and learning orientation in sixth form so as to be in line with the orientation of teaching and learning in colleges and universities. The revision of the Chemistry syllabus incorporates current developments in chemistry studies and syllabus design in Malaysia. The syllabus will give candidates exposure to pre-university level about Chemistry as a central science that includes physical chemistry, inorganic chemistry and organic chemistry. In tandem with the global needs for a sustainable environment, it is important to promote awareness of the roles of chemistry in the understanding of nature and the universe. As such, environmental chemistry relating to green chemistry as well as water and solid waste management has been included in this revised syllabus. Accordingly, it is hoped that this syllabus will be able to produce pre-university candidates which are mature minded, knowledgeable, and able to communicate idea effectively using various forms of communications. The syllabus contains topics, teaching periods, learning outcomes, examination format, grade description, and sample questions. The design of this syllabus was undertaken by a committee chaired by Professor Datuk Dr. A. Hamid bin A. Hadi from University of Malaya. Other committee members consist of university lecturers, representatives from the Curriculum Development Division, Ministry of Education Malaysia, and experienced teachers teaching Chemistry. On behalf of the MEC, I would like to thank the committee for their commitment and invaluable contribution. It is hoped that this syllabus will be a guide for teachers and candidates in the teaching and learning process. OMAR BIN ABU BAKAR Chief Executive Malaysian Examinations Council

CONTENTS

Syllabus 962 Chemistry

Page Aims 1 Objectives 1 Content First Term 2 – 10 Second Term 11 – 18 Third Term 19 – 30 Practical Syllabus (School-based Assessment of Practical (Paper 4)) 31 – 32 Written Practical Test (Paper 5) 32 – 33 Scheme of Assessment 34 – 35 Performance Descriptions 36 Summary of Key Quantities and Units 37 – 38 Periodic Table 39 Reference Books 40 Specimen Paper 1 41 – 57 Specimen Paper 2 59 – 77 Specimen Paper 3 79– 95 Specimen Experiment Paper 4 97 – 99 Specimen Paper 5 101 – 123

1

SYLLABUS 962 CHEMISTRY

Aims This syllabus aims to enhance candidates knowledge and understanding of chemistry. It also enables them to advance their studies at institutions of higher learning and assists them to pursue a chemistry-related career. It will also promote awareness of the roles of chemistry in the understanding of nature and the universe. Objectives The objectives of this syllabus are to enable the candidates to:

(a) understand facts, terminologies and principles of chemistry;

(b) interpret phenomena by using models, laws and chemical principles;

(c) interpret and apply scientific information presented in various forms;

(d) solve problems related to chemistry;

(e) analyse, synthesise and evaluate information and ideas logically and critically;

(f) plan, carry out experiments, draw inferences and make deductions;

(g) use scientific equipment properly and safely;

(h) develop positive attitudes and values towards the environment;

(i) acquire generic skills.

2

FIRST TERM

Topic Teaching Period Learning Outcome

1 Atoms, Molecules and Stoichiometry 1.1 Fundamental particles

of an atom

8

2

Candidates should be able to: (a) describe the properties of protons, neutrons

and electrons in terms of their relative charges and relative masses;

(b) predict the behaviour of beams of protons, neutrons and electrons in both electric and magnetic fields;

(c) describe the distribution of mass and charges within an atom;

(d) determine the number of protons, neutrons and electrons present in both neutral and charged species of a given proton number and nucleon number;

(e) describe the contribution of protons and neutrons to atomic nuclei in terms of proton number and nucleon number;

(f) distinguish isotopes based on the number of neutrons present, and state examples of both stable and unstable isotopes.

1.2 Relative atomic,

isotopic, molecular and formula masses

3 Candidates should be able to: (a) define the terms relative atomic mass, Ar,

relative isotopic mass, relative molecular mass, Mr, and relative formula mass based on 12C;

(b) interpret mass spectra in terms of relative abundance of isotopes and molecular fragments;

(c) calculate relative atomic mass of an element from the relative abundance of its isotopes or its mass spectrum.

3


1.3 The mole and the

Avogadro constant 3 Candidates should be able to:

(a) define mole in terms of the Avogadro constant;

(b) calculate the number of moles of reactants, volumes of gases, volumes of solutions and concentrations of solutions;

(c) deduce stoichiometric relationships from the calculations above.

2 Electronic Structure of Atoms 2.1 Electronic energy

levels of atomic hydrogen

8

2

Candidates should be able to: (a) explain the formation of the emission line

spectrum of atomic hydrogen in the Lyman and Balmer series using Bohr’s Atomic Model.

2.2 Atomic orbitals: s, p and d

2 Candidates should be able to: (a) deduce the number and relative energies of the

s, p and d orbitals for the principal quantum numbers 1, 2 and 3, including the 4s orbitals;

(b) describe the shape of the s and p orbitals. 2.3 Electronic

configuration

2 Candidates should be able to: (a) predict the electronic configuration of atoms

and ions given the proton number (and charge);

(b) define and apply Aufbau principle, Hund’s rule and Pauli exclusion principle.

2.4 Classification of

elements into s, p, d and f blocks in the Periodic Table

2 Candidates should be able to: (a) identify the position of the elements in the

Periodic Table as

(i) block s, with valence shell configurations s1 and s2,

(ii) block p, with valence shell configurations from s2p1 to s2p6,

(iii) block d, with valence shell configurations from d1s2 to d10s2;

(b) identify the position of elements in block f of the Periodic Table.

4


3 Chemical Bonding 3.1 Ionic bonding

20

1

Candidates should be able to: (a) describe ionic (electrovalent) bonding as

exemplified by NaCl and MgCl2. 3.2 Covalent bonding

15 Candidates should be able to: (a) draw the Lewis structure of covalent molecules

(octet rule as exemplified by NH3, CCl4, H2O, CO2, N2O4 and exception to the octet rule as exemplified by BF3, NO, NO2, PCl5, SF6);

(b) draw the Lewis structure of ions as exemplified by SO4

2−, CO32−, NO3

− and CN−;

(c) explain the concept of overlapping and hybridisation of the s and p orbitals as exemplified by BeCl2, BF3, CH4, N2, HCN, NH3 and H2O molecules;

(d) predict and explain the shapes of and bond

angles in molecules and ions using the principle of valence shell electron pair repulsion, e.g. linear, trigonal planar, tetrahedral, trigonal bipyramid, octahedral, V-shaped, T-shaped, seesaw and pyramidal;

(e) explain the existence of polar and non-polar bonds (including C−C1, C−N, C−O, C−Mg) resulting in polar or/and non-polar molecules;

(f) relate bond lengths and bond strengths with respect to single, double and triple bonds;

(g) explain the inertness of nitrogen molecule in terms of its strong triple bond and non-polarity;

(h) describe typical properties associated with ionic and covalent bonding in terms of bond strength, melting point and electrical conductivity;

(i) explain the existence of covalent character in ionic compounds such as A12O3, A1I3 and LiI;

(j) explain the existence of coordinate (dative covalent) bonding as exemplified by H3O+, NH4

+, A12C16 and [Fe(CN)6]3−.

5


3.3 Metallic bonding

1

Candidates should be able to: (a) explain metallic bonding in terms of electron

sea model. 3.4 Intermolecular forces: van der Waals forces and hydrogen bonding

3 Candidates should be able to: (a) describe hydrogen bonding and van der Waals

forces (permanent, temporary and induced dipole);

(b) deduce the effect of van der Waals forces between molecules on the physical properties of substances;

(c) deduce the effect of hydrogen bonding (intermolecular and intramolecular) on the physical properties of substances.

4 States of Matter 4.1 Gases

14

6

Candidates should be able to: (a) explain the pressure and behaviour of ideal gas

using the kinetic theory;

(b) explain qualitatively, in terms of molecular size and intermolecular forces, the conditions necessary for a gas approaching the ideal behaviour;

(c) define Boyle’s law, Charles’ law and Avogadro’s law;

(d) apply the pV = nRT equation in calculations, including the determination of the relative molecular mass, Mr;

(e) define Dalton’s law, and use it to calculate the partial pressure of a gas and its composition;

(f) explain the limitation of ideality at very high pressures and very low temperatures.

4.2 Liquids 2 Candidates should be able to:

(a) describe the kinetic concept of the liquid state;

(b) describe the melting of solid to liquid, vaporisation and vapour pressure using simple kinetic theory;

(c) define the boiling point and freezing point of liquids.

6


4.3 Solids 2 Candidates should be able to:

(a) describe qualitatively the lattice structure of a

crystalline solid which is:

(i) ionic, as in sodium chloride,

(ii) simple molecular, as in iodine,

(iii) giant molecular, as in graphite, diamond and silicon(IV) oxide,

(iv) metallic, as in copper;

(b) describe the allotropes of carbon (graphite, diamond and fullerenes), and their uses.

4.4 Phase diagrams 4

Candidates should be able to: (a) sketch the phase diagram for water and carbon

dioxide, and explain the anomalous behaviour of water;

(b) explain phase diagrams as graphical plots of experimentally determined results;

(c) interpret phase diagrams as curves describing the conditions of equilibrium between phases and as regions representing single phases;

(d) predict how a phase may change with changes in temperature and pressure;

(e) discuss vaporisation, boiling, sublimation, freezing, melting, triple and critical points of H2O and CO2;

(f) explain qualitatively the effect of a non-volatile solute on the vapour pressure of a solvent, and hence, on its melting point and boiling point (colligative properties);

(g) state the uses of dry ice.

5. Reaction Kinetics 5.1 Rate of reaction

14

2

Candidates should be able to: (a) define rate of reaction, rate equation, order of

reaction, rate constant, half-life of a first-order reaction, rate determining step, activation energy and catalyst;

(b) explain qualitatively, in terms of collision theory, the effects of concentration and temperature on the rate of a reaction.

7


5.2 Rate law

4 Candidates should be able to: (a) calculate the rate constant from initial rates;

(b) predict an initial rate from rate equations and experimental data;

(c) use titrimetric method to study the rate of a given reaction.

5.3 The effect of temperature on reaction kinetics

1 Candidates should be able to: (a) explain the relationship between the rate

constants with the activation energy and temperature using Arrhenius equation

(b) use the Boltzmann distribution curve to explain the distribution of molecular energy.

5.4 The role of catalysts in reactions

2 Candidates should be able to: (a) explain the effect of catalysts on the rate of a

reaction;

(b) explain how a reaction, in the presence of a catalyst, follows an alternative path with a lower activation energy;

(c) explain the role of atmospheric oxides of nitrogen as catalysts in the oxidation of atmospheric sulphur dioxide;

(d) explain the role of vanadium(V) oxide as a catalyst in the Contact process;

(e) describe enzymes as biological catalysts.

5.5 Order of reactions and rate constants

5 Candidates should be able to: (a) deduce the order of a reaction (zero-, first- and

second-) and the rate constant by the initial rates method and graphical methods;

(b) verify that a suggested reaction mechanism is consistent with the observed kinetics;

(c) use the half-life (t½) of a first-order reaction in calculations.

k = ;aE

RTAe−

8


6 Equilibria 6.1 Chemical equilibria

32

10

Candidates should be able to: (a) describe a reversible reaction and dynamic

equilibrium in terms of forward and backward reactions;

(b) state mass action law from stoichiometric equation;

(c) deduce expressions for equilibrium constants in terms of concentrations, Kc, and partial pressures, Kp, for homogeneous and heterogeneous systems;

(d) calculate the values of the equilibrium constants in terms of concentrations or partial pressures from given data;

(e) calculate the quantities present at equilibrium from given data;

(f) apply the concept of dynamic chemical equilibrium to explain how the concentration of stratospheric ozone is affected by the photodissociation of NO2, O2 and O3 to form reactive oxygen radicals;

(g) state the Le Chatelier’s principle and use it to discuss the effect of catalysts, changes in concentration, pressure or temperature on a system at equilibrium in the following examples:

(i) the synthesis of hydrogen iodide, (ii) the dissociation of dinitrogen tetroxide, (iii) the hydrolysis of simple esters, (iv) the Contact process, (v) the Haber process, (vi) the Ostwald process;

(h) explain the effect of temperature on equilibrium constant from the equation

ln K = CRT

H+−

Δ .

6.2 Ionic equilibria

10 Candidates should be able to: (a) use Arrhenius, BrØnsted-Lowry and Lewis

theories to explain acids and bases;

(b) identify conjugate acids and bases;

9


(c) explain qualitatively the different properties of

strong and weak electrolytes;

(d) explain and calculate the terms pH, pOH, Ka, pKa, Kb, pKb, Kw and pKw from given data;

(e) explain changes in pH during acid-base titrations;

(f) explain the choice of suitable indicators for acid-base titrations;

(g) define buffer solutions;

(h) calculate the pH of buffer solutions from given data;

(i) explain the use of buffer solutions and their importance in biological systems such as the role of H2CO3

/ HCO3− in controlling pH in

blood. 6.3 Solubility equilibria

5 Candidates should be able to: (a) define solubility product, Ksp;

(b) calculate Ksp from given concentrations and vice versa;

(c) describe the common ion effect, including buffer solutions;

(d) predict the possibility of precipitation from solutions of known concentrations;

(e) apply the concept of solubility equilibria to describe industrial procedure for water softening.

6.4 Phase equilibria 7

Candidates should be able to: (a) state and apply Raoult’s law for two miscible

liquids;

(b) interpret the boiling point-composition curves for mixtures of two miscible liquids in terms of ‘ideal’ behaviour or positive or negative deviations from Raoult’s law;

(c) explain the principles involved in fractional distillation of ideal and non ideal liquid mixtures;

10


(d) explain the term azeotropic mixture;

(e) explain the limitations on the separation of two components forming an azeotropic mixture;

(f) explain qualitatively the advantages and disadvantages of fractional distillation under reduced pressure.

11

SECOND TERM


7 Chemical Energetics 7.1 Enthalpy changes of reaction, ΔH

18

6

Candidates should be able to: (a) explain that most chemical reactions are

accompanied by enthalpy changes (exothermic or endothermic);

(b) define enthalpy change of reaction, ΔH, and state the standard conditions;

(c) define enthalpy change of formation, combustion, hydration, solution, neutralisation, atomisation, bond energy, ionisation energy and electron affinity;

(d) calculate the heat energy change from experimental measurements using the relationship: heat change, q = mcΔT or q = mcθ ;

(e) calculate enthalpy changes from experimental results.

7.2 Hess’ law

6 Candidates should be able to: (a) state Hess’ law, and its use to find enthalpy

changes that cannot be determined directly, e.g. an enthalpy change of formation from enthalpy changes of combustion;

(b) construct energy level diagrams relating the enthalpy to reaction path and activation energy;

(c) calculate enthalpy changes from energy cycles. 7.3 Born-Haber cycle 4 Candidates should be able to:

(a) define lattice energy for simple ionic crystals

in terms of the change from gaseous ions to solid lattice;

(b) explain qualitatively the effects of ionic charge and ionic radius on the numerical magnitude of lattice energy values;

(c) construct Born-Haber cycle for the formation of simple ionic crystals.

12


7.4 The solubility of solids in liquids

2 Candidates should be able to: (a) construct energy cycles for the formation of

aqueous solutions of ionic compounds;

(b) explain qualitatively the influence on solubility of the relationship between enthalpy change of solution, lattice energy of solid and enthalpy change of hydration or other solvent-solute interaction.

8 Electrochemistry 8.1 Half-cell and redox equations

26

2

Candidates should be able to: (a) explain the redox processes and cell diagram

(cell notation) of the Daniell cell;

(b) construct redox equations. 8.2 Standard electrode potential

9 Candidates should be able to: (a) describe the standard hydrogen electrode;

(b) use the standard hydrogen electrode to determine standard electrode potential (standard reduction potential), Eº;

(c) calculate the standard cell potential using the Eo values, and write the redox equations;

(d) predict the stability of aqueous ions from Eº values;

(e) predict the power of oxidising and reducing agents from Eº values;

(f) predict the feasibility of a reaction from value and from the combination of various electrode potentials: spontaneous and non-spontaneous electrode reactions.

8.3 Non-standard cell potentials

3 Candidates should be able to: (a) calculate the non-standard cell potential, Ecell,

of a cell using the Nernst equation. 8.4 Fuel cells

2 Candidates should be able to: (a) describe the importance of the development of

more efficient batteries for electric cars in terms of smaller size, lower mass and higher voltage, as exemplified by hydrogen-oxygen fuel cell.

Eºcell

13


8.5 Electrolysis 6 Candidates should be able to:

(a) compare the principles of electrolytic cell to

electrochemical cell;

(b) predict the products formed during electrolysis;

(c) state the Faraday’s first and second laws of electrolysis;

(d) state the relationship between the Faraday constant, the Avogadro constant and the electronic charge;

(e) calculate the quantity of electricity used, the mass of material and/or gas volume liberated during electrolysis.

8.6 Applications of electrochemistry

4 Candidates should be able to: (a) explain the principles of electrochemistry in

the process and prevention of corrosion (rusting of iron);

(b) describe the extraction of aluminium by electrolysis, and state the advantages of recycling aluminium;

(c) describe the process of anodisation of aluminium to resist corrosion;

(d) describe the diaphragm cell in the manufacture of chlorine from brine;

(e) describe the treatment of industrial effluent by electrolysis to remove Ni2+, Cr3+ and Cd2+;

(f) describe the electroplating of coated plastics. 9 Periodic Table: Periodicity 9.1 Physical properties of elements of Period 2 and Period 3

10

5

Candidates should be able to: (a) interpret and explain the trend and gradation

of atomic radius, melting point, boiling point, enthalpy change of vaporisation and electrical conductivity in terms of structure and bonding;

(b) explain the factors influencing ionisation energies;

(c) explain the trend in ionisation energies across Period 2 and Period 3 and down a group;

14


(d) predict the electronic configuration and

position of unknown elements in the Periodic Table from successive values of ionisation energies.

9.2 Reactions of Period 3 elements with oxygen and water

2 Candidates should be able to: (a) describe the reactions of Period 3 elements

with oxygen and water;

(b) interpret the ability of elements to act as oxidising and reducing agents.

9.3 Acidic and basic properties of oxides and hydrolysis of oxides

3 Candidates should be able to: (a) explain the acidic and basic properties of the

oxides of Period 3 elements;

(b) describe the reactions of the oxides of Period 3 elements with water;

(c) describe the classification of the oxides of Period 3 elements as basic, amphoteric or acidic based on their reactions with water, acid and alkali;

(d) describe the use of sulphur dioxide in food preservation.

10 Group 2 10.1 Selected Group 2 elements and their compounds

10

7

Candidates should be able to: (a) describe the trends in physical properties of

Group 2 elements: Mg, Ca, Sr, Ba;

(b) describe the reactions of Group 2 elements with oxygen and water;

(c) describe the behaviour of the oxides of Group 2 elements with water;

(d) explain qualitatively the thermal decomposition of the nitrates, carbonates and hydroxides of Group 2 elements in terms of the charge density and polarisability of large anions;

(e) explain qualitatively the variation in solubility of sulphate of Group 2 elements in terms of the relative magnitudes of the enthalpy change of hydration for the relevant ions and the corresponding lattice energy.

15


10.2 Anomalous behaviour of beryllium

2

Candidates should be able to: (a) explain the anomalous behaviour of beryllium

as exemplified by the formation of covalent compounds;

(b) describe the diagonal relationships between beryllium and aluminium;

(c) explain the similarity of aqueous beryllium salts to aqueous aluminium salts in terms of their acidic property.

10.3 Uses of Group 2 compounds

1 Candidates should be able to: (a) state the uses of Group 2 compounds in

agriculture, industry and medicine. 11 Group 14 11.1 Physical properties of Group 14 elements

10

2

Candidates should be able to: (a) explain the trends in physical properties

(melting points and electrical conductivity) of Group 14 elements: C, Si, Ge, Sn, Pb.

11.2 Tetrachlorides and oxides of Group 14 elements

4 Candidates should be able to: (a) explain the bonding and molecular shapes of

the tetrachlorides of group 14 elements;

(b) explain the volatility, thermal stability and hydrolysis of tetrachlorides in terms of structure and bonding;

(c) explain the bonding, acid-base nature and the thermal stability of the oxides of oxidation states +2 and +4.

11.3 Relative stability of +2 and +4 oxidation states of Group 14 elements

2 Candidates should be able to: (a) explain the relative stability of +2 and +4

oxidation states of the elements in their oxides, chlorides and aqueous cations.

11.4 Silicon, silicone and silicates

1 Candidates should be able to: (a) describe the structures of silicone and silicates

(pyroxenes and amphiboles), sheets (mica) and framework structure (quartz) (general formulae are not required);

16


(b) explain the uses of silicon as a semiconductor

and silicone as a fluid, elastomer and resin;

(c) describe the uses of silicates as basic materials for cement, glass, ceramics and zeolites.

11.5 Tin alloys 1 Candidates should be able to:

(a) describe the uses of tin in solder and pewter.

12 Group 17 12.1 Physical properties of selected Group 17 elements

8

1

Candidates should be able to: (a) state that the colour intensity of Group 17

elements: Cl2, Br2, I2, increase down the group;

(b) explain how the volatility of Group 17 elements decreases down the group.

12.2 Reactions of selected Group 17 elements

4 Candidates should be able to: (a) deduce and explain the relative reactivities of

Group 17 elements as oxidising agents from Eº values;

(b) explain the order of reactivity of F2, Cl2, Br2, I2 with hydrogen, and compare the relative thermal stabilities of the hydrides;

(c) explain the reactions of chlorine with cold and hot aqueous sodium hydroxide.

12.3 Reactions of selected halide ions

2 Candidates should be able to: (a) explain and write equations for reactions of

Group 17 ions with aqueous silver ions followed by aqueous ammonia;

(b) explain and write equations for reactions of Group 17 ions with concentrated sulphuric acid.

12.4 Industrial applications of halogens and their compounds

1 Candidates should be able to: (a) describe the industrial uses of the halogens and

their compounds as antiseptic, bleaching agent and in black-and-white photography;

(b) explain the use of chlorine in water treatment.

17


13 Transition Elements 13.1 Physical properties of first row transition elements

14

2

Candidates should be able to: (a) define a transition element in terms of

incomplete d orbitals in at least one of its ions;

(b) describe the similarities in physical properties such as atomic radius, ionic radius and first ionisation energy;

(c) explain the variation in successive ionisation energies;

(d) contrast qualitatively the melting point, density, atomic radius, ionic radius, first ionisation energy and conductivity of the first row transition elements with those of calcium as a typical s-block element.

13.2 Chemical properties of first row transition elements

8 Candidates should be able to: (a) explain variable oxidation states in terms of

the energies of 3d and 4s orbitals;

(b) explain the colours of transition metal ions in terms of a partially filled 3d orbitals;

(c) state the principal oxidation numbers of these elements in their common cations, oxides and oxo ions;

(d) explain qualitatively the relative stabilities of these oxidation states;

(e) explain the uses of standard reduction potentials in predicting the relative stabilities of aqueous ions;

(f) explain the terms complex ion and ligand; (g) explain the formation of complex ions and the

colour changes by exchange of ligands. (Examples of ligands: water, ammonia, cyanide ions, thiocyanate ions, ethanedioate ions, ethylenediaminetetraethanoate, halide ions; examples of complex ions: [Fe(CN)6]4−, [Fe(CN)6]3−, [Fe(H2O)5(SCN)]2+);

(h) explain the use of first row transition elements in homogeneous catalysis, as exemplifed by Fe2+ or Fe3+ in the reaction between I− and S2O8

2−;

18


(i) explain the use of first row transition elements

in heterogeneous catalysis, as exemplifed by Ni and Pt in the hydrogenation of alkenes.

13.3 Nomenclature and bonding of complexes

3

Candidates should be able to: (a) name complexes using International Union of

Pure and Applied Chemistry (IUPAC) nomenclature;

(b) discuss coordinate bond formation between ligands and the central metal atom/ion, and state the types of ligands, i.e. monodentate, bidentate and hexadentate.

13.4 Uses of first row transition elements and their compounds

1 Candidates should be able to: (a) describe the use of chromium (in stainless

steel), cobalt, manganese, titanium (in alloys) and TiO2 (in paints).

19

THIRD TERM


14 Introduction to Organic Chemistry

21

14.1 Bonding of the carbon atoms: the shapes of ethane, ethene, ethyne and benzene molecules

4 Candidates should be able to: (a) use the concept of sp3, sp2 and sp

hybridisations in carbon atoms to describe the bonding and shapes of molecules as exemplified by CH4, C2H4, C2H2 and C6H6;

(b) explain the concept of delocalisation of π electrons in benzene ring.

14.2 General, empirical, molecular and structural formulae of organic compounds

2 Candidates should be able to: (a) state general, empirical, molecular and

structural formulae of organic compounds;

(b) determine empirical and molecular formulae of organic compounds.

14.3 Functional groups: classification and nomenclature

2 Candidates should be able to: (a) describe the classification of organic

compounds by functional groups and the nomenclature of classes of organic compounds according to the IUPAC rules of the following classes of compounds:

(i) alkanes, alkenes, alkynes and arenes,

(ii) haloalkanes,

(iii) alcohols (including primary, secondary and tertiary) and phenols,

(iv) aldehydes and ketones,

(v) carboxylic acids and their derivatives (acyl chlorides, amides and esters),

(vi) primary amines, amino acids and protein.

14.4 Isomerism: structural and stereoisomerism

3 Candidates should be able to: (a) define structural and stereoisomerism

(geometrical and optical);

(b) explain the meaning of a chiral centre in optical isomerism;

20


(c) classify isomers as structural, cis-trans and

optical isomers;

(d) identify chiral centres and/or cis-trans isomerism in a molecule of given structural formula;

(e) deduce the possible isomers for an organic compound of known molecular formula.

14.5 Free radicals, nucleophiles and electrophiles

4 Candidates should be able to: (a) describe homolytic and heterolytic fissions;

(b) define the terms free radical, nucleophile and electrophile;

(c) explain that nucleophiles such as OH−, NH3, H2O, Br−, I− and carbanion are Lewis bases;

(d) explain that electrophiles such as H+, NO2+,

Br2, A1C13, ZnC12, FeBr3, BF3 and carbonium ion are Lewis acids.

14.6 Molecular structure and its effect on physical properties

2 Candidates should be able to: (a) describe the relationship between the size of

molecules in the homologous series and the melting and boiling points;

(b) explain the forces of attraction between molecules (van der Waals forces and hydrogen bonding).

14.7 Inductive and resonance effect

4 Candidates should be able to: (a) explain inductive effect which can determine

the properties and reactions of functional groups;

(b) use inductive effect to explain why functional groups such as −NO2, −CN, −COOH, −COOR, >C=O, −SO3H, −X (halogen), −OH, −OR, −NH2, −C6H5 are electron acceptors whereas R(alkyl) is an electron donor;

(c) explain how the concept of induction can account for the differences in acidity between CH3COOH, C1CH2COOH, C12CHCOOH and Cl3CCOOH; between C1CH2CH2CH2COOH and CH3CH2CHClCOOH;

21


(d) use the concept of resonance to explain the

differences in acidity between CH3CH2OH and C6H5OH, as well as the differences in basicity between CH3NH2 and C6H5NH2.

15 Hydrocarbons 15.1 Alkanes

21

7

Candidates should be able to: (a) write the general formula for alkanes;

(b) explain the construction of the alkane series (straight and branched), and IUPAC nomenclature of alkanes for C1 to C10;

(c) describe the structural isomerism in aliphatic alkanes and cis-trans isomerism in cycloalkanes;

(d) state the physical properties of alkanes;

(e) define alkanes as saturated aliphatic hydrocarbons;

(f) name alkyl groups derived from alkanes and identify primary, secondary, tertiary and quartenary carbons;

(g) explain the inertness of alkanes towards polar reagents;

(h) describe the mechanism of free radical substitution as exemplified by the chlorination of methane (with particular reference to the initiation, propagation and termination reactions);

(i) describe the oxidation of alkane with limited and excess oxygen, and the use of alkanes as fuels;

(j) explain the use of crude oil as a source of aliphatic hydrocarbons;

(k) explain how cracking reactions can be used to obtain alkanes and alkenes of lower Mr from larger hydrocarbon molecules;

(l) discuss the role of catalytic converters in minimising air pollution by oxidising CO to CO2 and reducing NOx to N2;

(m) explain how chemical pollutants from the combustion of hydrocarbon affect air quality and rainwater as exemplified by acid rain, photochemical smog and greenhouse effect.

22


15.2 Alkenes 6 Candidates should be able to:

(a) write the general formula for alkenes;

(b) name alkenes according to the IUPAC nomenclature and their common names for C1 to C5;

(c) describe structural and cis-trans isomerism in alkenes;

(d) state the physical properties of alkenes;

(e) define alkenes as unsaturated aliphatic hydrocarbons with one or more double bonds;

(f) describe the chemical reactions of alkenes as exemplified by the following reactions of ethene:

(i) addition of hydrogen, steam, hydrogen halides, halogens, bromine water and concentrated sulphuric acid,

(ii) oxidation using KMnO4, O2/Ag,

(iii) ozonolysis,

(iv) polymerisation;

(g) describe the mechanism of electrophilic addition in alkenes with reference to Markovnikov’s rule;

(h) explain the use of bromination reaction and decolourisation of MnO4

− ions as simple tests for alkenes and unsaturated compounds;

(i) explain briefly the importance of ethene as a source for the preparation of chloroethane, epoxyethane, ethane-1,2-diol and poly(ethane).

15.3 Arenes 8 Candidates should be able to:

(a) name aromatic compounds derived from

benzene according to the IUPAC nomenclature, including the use of ortho, meta and para or the numbering of substituted groups to the benzene ring;

(b) describe structural isomerism in arenes;

23


(c) describe the chemical reactions of arenes as exemplified by substitution reactions of haloalkanes and acyl chloride (Friedel-Crafts reaction), halogen, conc. HNO3/conc. H2SO4 and SO3 with benzene and methylbenzene (toluene);

(d) describe the mechanism of electrophilic substitution in arenes as exemplified by the nitration of benzene;

(e) explain why benzene is more stable than aliphatic alkenes towards oxidation;

(f) describe the reaction between alkylbenzene and hot acidified KMnO4;

(g) determine the products of halogenation of methylbenzene (toluene) in the presence of

(i) Lewis acid catalysts,

(ii) light;

(h) explain the inductive effect and resonance effect of substituted groups (−OH, −C1, −CH3, −NO2, −COCH3, −NH2) attached to the benzene ring towards further substitutions;

(i) predict the products in an electrophilic substitution reaction when the substituted group in benzene is electron accepting or electron donating;

(j) explain the uses of arenes as solvents;

(k) recognise arenes as carcinogen.

16 Haloalkanes 8 Candidates should be able to: (a) write the general formula for haloalkanes;

(b) name haloalkanes according to the IUPAC nomenclature;

(c) describe the structural and optical isomerism in haloalkanes;

(d) state the physical properties of haloalkanes;

(e) describe the substitution reactions of haloalkanes as exemplified by the following reactions of bromoethane: hydrolysis, the formation of nitriles and the formation of primary amines;

24


(f) describe the elimination reactions of

haloalkanes;

(g) describe the mechanism of nucleophilic substitution in haloalkanes (SN1 and SN2);

(h) explain the relative reactivity of primary, secondary and tertiary haloalkanes;

(i) compare the reactivity of chlorobenzene and chloroalkanes in hydrolysis reactions;

(j) explain the use of haloalkanes in the synthesis of organomagnesium compounds (Grignard reagents), and their use in reactions with carbonyl compounds;

(k) describe the uses of fluoroalkanes and chlorofluoroalkanes as inert substances for aerosol propellants, coolants and fire-extinguishers;

(l) state the use of chloroalkanes as insecticide such as DDT;

(m) describe the effect of chlorofluoroalkanes in the depletion of the ozone layer, and explain its mechanism.

17 Hydroxy Compounds 17.1 Introduction to hydroxy compounds

12

1

Candidates should be able to: (a) write the general formula for hydroxy

compounds;

(b) name hydroxy compounds according to the IUPAC nomenclature;

(c) describe structural and optical isomerism in hydroxy compounds;

(d) state the physical properties of hydroxy compounds.

17.2 Alcohols 6 Candidates should be able to:

(a) classify alcohols into primary, secondary and

tertiary alcohol;

(b) classify the reactions of alcohols whereby the RO−H bond is broken: the formation of an alkoxide with sodium, esterification, acylation, oxidation to carbonyl compounds and carboxylic acids;

25


(c) classify the reactions of alcohols whereby the

R−OH is broken and −OH is replaced by other groups: the formation of haloalkanes and the dehydration to alkenes and ethers;

(d) explain the relative reactivity of primary, secondary and tertiary alcohols as exemplified by the reaction rate of such alcohols to give haloalkanes, and the reaction products of KMnO4/K2Cr2O7 oxidation in the presence of sulphuric acid;

(e) explain the reaction of alcohol with the structure CH3CH(OH)− with alkaline aqueous solution of iodine to form triiodomethane;

(f) describe the laboratory and industrial preparation of alcohol as exemplified by ethanol from the hydration of ethane;

(g) describe the synthesis of ethanol by fermentation process;

(h) state the uses of alcohols as antiseptic, solvent and fuel.

17.3 Phenols 5 Candidates should be able to:

(a) explain the relative acidity of water, phenol

and ethanol with particular reference to the inductive and resonance effects;

(b) describe the reactions of phenol with sodium hydroxide, sodium, acyl chlorides and electrophilic substitution in the benzene ring;

(c) describe the use of bromine water and aqueous iron(III) chloride as tests for phenol;

(d) describe the cumene process in the manufacture of phenol;

(e) explain the use of phenol in the manufacture of cyclohexanol, and hence, nylon-6,6.

18 Carbonyl Compounds 8 Candidates should be able to:

(a) write the general formula for carbonyl

compounds: aliphatic and aromatic aldehydes and ketones;

(b) name aliphatic and aromatic aldehydes and ketones according to the IUPAC nomenclature;

26


(c) describe structural and optical isomerism in

carbonyl compounds;

(d) state the physical properties of aliphatic and aromatic aldehydes and ketones;

(e) write the equations for the preparation of aldehydes and ketones;

(f) explain the reduction reactions of aldehydes and ketones to primary and secondary alcohols respectively through catalytic hydrogenation reaction and with LiA1H4;

(g) explain the use of 2,4-dinitrophenylhydrazine reagent as a simple test to detect the presence of >C=O groups;

(h) explain the mechanism of the nucleophilic addition reactions of hydrogen cyanide with aldehydes and ketones;

(i) explain the oxidation of aldehydes;

(j) differentiate between aldehyde and ketone based on the results of simple tests as exemplified by Fehling’s solution and Tollens’ reagent;

(k) explain the reactions of carbonyl compounds with the structure CH3−C=O with alkaline

aqueous solution of iodine to give triiodomethane (iodoform test);

(l) explain that natural compounds such as glucose, sucrose and other carbohydrates which have the >C=O group;

(m) explain the characteristics of glucose as a reducing sugar.

19 Carboxylic Acids and their Derivatives

10

19.1 Carboxylic acid 4

Candidates should be able to:

(a) write the general formula for aliphatic and aromatic carboxylic acids;

(b) name carboxylic acids according to the IUPAC nomenclature and their common names for C1 to C6;

(c) describe structural and optical isomerism in carboxylic acids;

27


(d) state the physical properties of carboxylic

acids;

(e) write the equations for the formation of carboxylic acids from alcohols, aldehydes and nitriles;

(f) describe the acidic properties of carboxylic acids as exemplified by their reactions with metals and bases to form salts;

(g) explain the substitution of the −OH in carboxylic acids by the nucleophiles −OR and −C1 to form esters and acyl chlorides respectively;

(h) describe the reduction of carboxylic acids to primary alcohols;

(i) describe the oxidation and dehydration of methanoic and ethanedioic acids (oxalic acid);

(j) state the uses of carboxylic acids in food, perfume and polymer industries.

19.2 Acyl chlorides 2 Candidates should be able to:

(a) write the general formula for acyl chlorides;

(b) name acyl chlorides according to the IUPAC nomenclature;

(c) describe structural and optical isomerism in acyl chlorides;

(d) state the physical properties of acyl chlorides;

(e) explain the ease of hydrolysis of acyl chlorides compared to chloroalkanes;

(f) describe the reactions of acyl chlorides with alcohols, phenols and primary amines.

19.3 Esters 2 Candidates should be able to:

(a) write the general formula for esters;

(b) name esters according to the IUPAC nomenclature;

(c) describe structural and optical isomerism in esters;

(d) state the physical properties of esters;

(e) describe the preparation of esters by the reactions of acyl chlorides with alcohols and phenols;

28


(f) describe the acid and base hydrolysis of esters;

(g) describe the reduction of esters to primary alcohols;

(h) state the uses of esters as flavourings, preservatives and solvents.

19.4 Amides 2 Candidates should be able to:

(a) write the general formula for amides;

(b) name amides according to the IUPAC nomenclature;

(c) describe structural and optical isomerism in amides;

(d) state the physical properties of amides;

(e) describe the preparation of amides by the reaction of acyl chlorides with primary amines;

(f) describe the acid and base hydrolysis of amides.

20 Amines, Amino Acids and

Proteins 20.1 Amines

8

4

Candidates should be able to:

(a) write the general formula for amines;

(b) name amines according to the IUPAC nomenclature and their common names;

(c) describe structural and optical isomerism in amines;

(d) state the physical properties of amines;

(e) classify amines into primary, secondary and tertiary amines;

(f) explain the relative basicity of ammonia, ethanamine and phenylamine (aniline) in terms of their structures;

(g) describe the preparation of ethanamine by the reduction of nitriles, and phenylamine by the reduction of nitrobenzene;

(h) explain the formation of salts when amines react with mineral acids;

(i) differentiate primary aliphatic amines from primary aryl (aromatic) amines by their respective reactions with nitric(III) acid (nitrous acid) and bromine water;

29


(j) explain the formation of dyes by the coupling reaction of the diazonium salt as exemplified by the reaction of benzenediazonium chloride with phenol.

20.2 Amino acids 3 Candidates should be able to:

(a) write the structure and general formula for

α-amino acids;

(b) name α-amino acids according to the IUPAC nomenclature and their common names;

(c) describe structural and optical isomerism in amino acids;

(d) state the physical properties of α-amino acids;

(e) describe the acid and base properties of α-amino acids;

(f) describe the formation of zwitterions;

(g) explain the peptide linkage as amide linkage formed by the condensation between two or more α-amino acids as exemplified by glycylalanine and alanilglycine.

20.3 Protein 1 Candidates should be able to:

(a) identify the peptide linkage in the primary

structure of protein;

(b) describe the hydrolysis of proteins;

(c) state the biological importance of proteins. 21 Polymers 8 Candidates should be able to: (a) state examples of natural and synthetic

polymers; (b) define monomer, polymer, repeating unit,

homopolymer and copolymer;

(c) identify the monomers in a polymer;

(d) describe condensation polymerisation as exemplified by terylene and nylon-6,6;

(e) describe addition polymerisation as exemplified by poly(ethene)/polyethylene/ polythene, poly(phenylethene)/polystyrene and poly(chloroethene)/polyvinylchloride;

30


(f) state the role of the Ziegler-Natta catalyst in

the addition polymerisation process;

(g) explain the classification of polymers as thermosetting, thermoplastic and elastomer;

(h) identify isoprene (2-methylbuta-1,3-diene) as the monomer of natural rubber;

(i) describe the two isomers in poly(2-methylbuta-1,3-diene) in terms of the elastic cis form (from the Hevea brasiliensis trees) and the inelastic trans form (from the gutta-percha trees);

(j) state the uses of polymers;

(k) explain the difficulty in the disposal of polymers;

(l) outline the advantages and disadvantages of dumping polymer-based materials in rivers and seas.

31

The Practical Syllabus

School-based Assessment of Practical (Paper 4) School-based assessment of practical works is carried out throughout the form six school terms for candidates from government and private schools which have been approved by the MEC to carry out the school-based assessment. MEC will determine 13 compulsory experiments and one project to be carried out by the candidates and to be assessed by the subject teachers in schools in the respective terms. The project will be carried out during the third term in groups of two or three candidates. Details of the title, topic, objective, theory, apparatus, and procedure of each of the experiments and project will be specified in the Teacher’s and Student’s Manual for Practical Chemistry which can be downloaded from MEC Portal (http://www.mpm.edu.my) during the first term of form six by the subject teachers. Candidates should be supplied with a work scheme before the day of the compulsory experiment so as to enable them to plan their practical work. Each experiment is expected to last one school double period. Assessment of the practical work is done by the subject teachers during the practical sessions and also based on the practical reports. The assessment should comply with the assessment guidelines prepared by MEC. A repeating candidate may use the total mark obtained in the coursework for two subsequent examinations. Requests to carry forward the moderated coursework mark should be made during the registration of the examination. Candidates will be assessed based on the following:

(a) the use and organisation of techniques, apparatus and materials,

(b) observations, measurements and recording,

(c) the interpretation of experimental observations and data,

(d) the designing and planning of investigations,

(e) scientific and critical attitudes. The Chemistry practical syllabus for STPM should achieve its objective to improve the quality of students in the aspects as listed below.

(a) The ability to follow a set or sequence of instructions.

(b) The ability to plan and carry out experiments using appropriate methods.

(c) The ability to choose suitable equipment and use them correctly and carefully.

(d) The ability to record readings from diagrams of apparatus.

(e) The ability to describe, explain, comment on or suggest experimental arrangements, techniques and procedures.

(f) The ability to complete tables of data and/or plot graphs.

(g) The ability to interpret, analyse and evaluate observations, experimental data and make deductions.

(h) The ability to do calculations based on experiments.

(i) The ability to make conclusions.

(j) The awareness of the safety measures which need to be taken.

http://www.mpm.edu.my/�

32

The objective of this project work is to enable candidates to acquire knowledge and skills in chemistry using information and communication technology as well as to develop soft skills as follows:

(a) communications,

(b) teamwork,

(c) critical thinking and problem solving,

(d) flexibility/adaptability,

(e) leadership,

(f) organising,

(g) information technology and communications,

(h) moral and ethics. Written Practical Test (Paper 5) The main objective of written practical test paper is to assess the candidates’ understanding of practical procedures in the laboratory. The following candidates are eligible to take this written practical test:

(a) individual private candidates,

(b) candidates from private schools which have no permission to carry out the school-based assessment of practical work,

(c) candidates who repeat upper six (in government or private schools),

(d) candidates who do not attend classes of lower six and upper six in two consecutive years (in government or private schools).

(e) candidates who take Chemistry other than the package offered by schools. Three structured questions on routine practical work and/or design of experiments will be set. MEC will not be strictly bound by the syllabus in setting questions. Where appropriate, candidates will be given sufficient information to enable them to answer the questions. Only knowledge of theory within the syllabus and knowledge of usual laboratory practical procedures will be expected. The questions to be set will test candidates’ ability to: (a) record readings from diagrams of apparatus, (b) describe, explain, comment on, or suggest experimental arrangements, techniques, and

procedures, (c) complete tables of data and/or plot graphs, (d) interpret, draw conclusions from and evaluate observations and experimental (including

graphical) data, (e) perform simple calculations based on experiments, (f) describe tests for gases, ions, oxidising and reducing agents, and/or make deductions from

such tests.

33

The questions to be set will cover the following three aspects:

(a) Volumetric analysis Experimental procedures and calculations such as purity determination and stoichiometry

from volumetric analysis of acid-base and redox titrations will be assessed. (b) Determination of physical quantities Experiments involving the measurements of selected quantities in the following topics:

thermochemistry, reaction kinetics, equilibrium, solubility and electrochemistry will be assessed.

(c) Techniques Techniques involving qualitative analysis of ions and functional groups and synthesis will

be assessed. It will be assumed that candidates will be familiar with the simple reactions of the following ions: NH4

+, Mg2+, Al3+, Ca2+, Cr3+, Mn2+, Fe2+, Fe3+, Ni2+, Cu2+, Zn2+, Ba2+, Pb2+, CO3

2−, NO3−, NO2

−, S2−, SO42−, SO3

2−, S2O32−, Cl−, Br−, I−, MnO4

−, CH3CO2−, C2O4

2−. Knowledge of simple organic reactions, e.g. test-tube reactions indicating the presence of

unsaturation and functional groups will be required. The substances to be asked in questions may contain ions not included in the above list; in

such cases, candidates will not be expected to identify the ions but to draw conclusions of a general nature.

34

Scheme of Assessment

Term of Study

Paper Code and Name Type of Test Mark

(Weighting) Duration Administration

First Term

962/1 Chemistry

Paper 1

Written Test

Section A 15 compulsory multiple-choice questions to be answered.

Section B 2 compulsory structured questions to be answered.

Section C 2 questions to be answered out of 3 essay questions.

All questions are based on topics 1 to 6.

60 (26.67%)

15

15

30

1½ hours Central assessment

Second Term

962/2 Chemistry

Paper 2

Written Test

Section A 15 compulsory multiple-choice questions to be answered.


Section C 2 questions to be answered out of 3 essay questions.

All questions are based on topics 7 to 13.

60 (26.67%)

15

15

30


Third Term

962/3 Chemistry

Paper 3

Written Test

Section A 15 compulsory multiple-choice to be answered.


Section C 2 questions to be answered out of 3 essay questions. All questions are based on topics 14 to 21.

60 (26.67%)

15

15

30


35

Term of Study

Paper Code and Name Type of Test Mark

(Weighting) Duration Administration

962/5 Chemistry

Paper 5

Written Practical Test

3 compulsory structured questions to be answered.

45 (20%)


First, Second

and Third Terms

962/4 Chemistry

Paper 4

School-based Assessment of Practical

13 compulsory experiments and one project to be carried out.

225 to be

scaled to 45 (20%)

Through-out the three terms

School-based assessment

36

Performance Descriptions A Grade A candidate is likely able to:

(a) relate facts to concepts, theories, principles and vice versa;

(b) explain why a particular technique is preferred for a procedure or operation;

(c) select and synthesise data from various sources and present it in a clear logical form;

(d) solve problems in any situation which may involve a wide range of variables;

(e) demonstrate an excellent use of generic skills. A Grade C candidate is likely able to:

(a) relate a few facts to concepts, theories and principles;

(b) follow the procedure(s) for a multiple step operation;

(c) use the given data and present it in a clear logical form;

(d) solve a problem involving more than one step, but with a limited range of variables;

(e) demonstrate a fair use of generic skills.

37

Summary of Key Quantities and Units The list below is intended as a guide for the common quantities which might be encountered in teaching and used in question papers. Quantity Common symbol Unit mass m kg, g length m time t s electric current I A amount of substance n mol temperature T °C, K temperature change θ , ΔT °C, K volume V m3, dm3, cm3

density ρ kg m−3, g dm−3, g cm−3 pressure p Pa, atm frequency ν Hz wavelength λ m, mm, nm speed of light c m s−1 Planck constant h J s electronic charge e C standard electrode potential E° V standard reduction potential E° V standard cell potential o

cellE V

cell potential cellE V

electromotive force E V gas constant R J K−1 mol−1 half-life

21t s

atomic mass unit − a.m.u. relative atomic mass Ar − relative isotopic mass Ar − relative molecular mass Mr − molar mass M g mol−1 Molar volume of gas Vm dm3 mol−1 nucleon number A − proton number Z − neutron number N − Avogadro constant L mol−1 Faraday constant F C mol−1 specific heat capacity c J g−1 °C−1 heat capacity C J °C−1 heat change q J, kJ enthalpy change of reaction ΔH J, kJ standard enthalpy change of reaction ΔH° J mol−1, kJ mol−1 ionisation energy I kJ mol−1 lattice energy o

latticeHΔ kJ mol−1

bond energy − kJ mol−1 electron affinity − kJ mol−1

38

Quantity Common symbol Unit rate constant k as appropriate equilibrium constant K, Kp, Kc as appropriate acid dissociation constant Ka mol dm−3 base dissociation constant Kb mol dm−3 mole fraction x − concentration c mol dm−3 solubility product Ksp as appropriate ionic product of water Kw mol2 dm−6

Periodic Table

Group 1 (I)

2 (II)

3 4 5 6 7 8 9 10 11 12 13 (III)

14 (IV)

15 (V)

16 (VI)

17 (VII)

18 (VIII)

1.0 H

1

4.0 He

2 6.9 Li

3

9.0 Be

4

a X

b

a = relative atomic mass X = atomic symbol b = proton number

10.8 B

5

12.0 C

6

14.0 N

7

16.0 O

8

19.0 F

9

20.2 Ne

10 23.0 Na

11

24.3 Mg

12

27.0 Al

13

28.1 Si

14

31.0 P

15

32.1 S

16

35.5 Cl

17

40.0 Ar

18 39.1

K 19

40.1 Ca

20

45.0 Sc

21

47.9 Ti

22

50.9 V

23

52.0 Cr

24

54.9 Mn

25

55.8 Fe

26

58.9 Co

27

58.7 Ni

28

63.5 Cu

29

65.4 Zn

30

69.7 Ga

31

72.6 Ge

32

74.9 As

33

79.0 Se

34

79.9 Br

35

83.8 Kr

36 85.5 Rb

37

87.6 Sr

38

88.9 Y

39

91.2 Zr

40

92.9 Nb

41

95.9 Mo

42

[98] Tc

43

101 Ru

44

103 Rh

45

106 Pd

46

108 Ag

47

112 Cd

48

115 In

49

119 Sn

50

122 Sb

51

128 Te

52

127 I

53

131 Xe

54 133 Cs

55

137 Ba

56

175.0 Lu

71

178 Hf

72

181 Ta

73

184 W

74

186 Re

75

190 Os

76

192 Ir

77

195 Pt

78

197 Au

79

201 Hg

80

204 Ti

81

207 Pb

82

209 Bi

83

[209] Po

84

[210] At

85

[222] Rn

86 [223]

Fr 87

[226] Ra

88

[262] Lr

103

[261] Rf

104

[262] Db

105

[263] Sg

106

[264] Bh

107

[265] Hs

108

[266] Mt

109

[269] Uuu]

110

[272] Uuu

111

[277] Uub

112

139 La

57

140 Ce

58

141 Pr

59

144 Nd

60

[145] Pm

61

150 Sm

62

152 Eu

63

157 Gd

64

159 Tb

65

163 Dy

66

165 Ho

67

167 Er

68

169 Tm

69

173 Yb

70

227

Ac 89

232 Th

90

231 Pa

91

238 U

92

237 Np

93

[244] Pu

94

[243] Am

95

[247] Cm

96

[247] Bk

97

[251] Cf

98

[252] Es

99

[257] Fm

100

[258] Md

101

[259] No

102

Lanthanides

Actinides

39

40

Reference Books Teachers and candidates may use books specially written for the STPM examination and other reference books such as those listed below. 1. Cann, P. and Hughes, P., 2002. Chemistry for Advanced Level. London: John Murray. 2. Clugston, M. and Flemming, R., 2000. Advanced Chemistry. New York: Oxford. 3. Lister, T. and Renshaw, J., 2000. Understanding Chemistry for Advanced Level. 3rd edition.

Cheltenham: Nelson Thornes. 4. Ramsden, E. N., 2000. A-Level Chemistry. 4th edition. Cheltenham: Nelson Thornes. 5. Brown, T. L. et al., 2006. Chemistry: The Central Science. 10th edition. New Jersey: Pearson. 6. Chang, R., 2007. Chemistry. 9th edition. New York: McGraw Hill. 7. Hill, G. and Holman, J., 2000. Chemistry in Context. 5th edition. Cheltenham: Nelson Thornes. 8. Moore, J.W., Stanitski, C. L., and Jurs, P.C., 2008. Chemistry The Molecular Science. 3rd

edition. California: Thomson Brooks/Cole. 9. Solomons, G. and Fryhle, C., 2008. Organic Chemistry. 9th edition. New Jersey: John Wiley &

Sons. 10. Brown, W. and Poon, T., 2005. Introduction to Organic Chemistry. 3rd edition. New Jersey:

John Wiley & Sons. 11. McMurry, J. and Simanek, E., 2007. Fundamentals of Organic Chemistry. 6th edition.

California: Thomson Brooks/Cole. 12. Housecroft, C. E. and Sharpe, A. G., 2005. Inorganic Chemistry. 2nd edition. Essex: Pearson. 13. Brady, J. E. and Senese, F., 2004. Chemistry. 4th edition. New Jersey: John Wiley & Sons. 14. Freemantle, M., 1997. Chemistry in Action. 2nd edition. London: Thomson Learning.

Identity card number: …………………………. Centre number/index number: ……………................ (Nombor kad pengenalan) (Nombor pusat/angka giliran)

41

SPECIMEN PAPER

962/1 STPM

CHEMISTRY (KIMIA)

PAPER 1 (KERTAS 1)

One and a half hours (Satu jam setengah)


SIJIL TINGGI PERSEKOLAHAN MALAYSIA (MALAYSIA HIGHER SCHOOL CERTIFICATE)

Instructions to candidates:

DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE TOLD TO DO SO. Answer all questions in Section A. Marks will not be deducted for wrong answers. For each question, four suggested answers are given. Choose the correct answer and circle the answer. Answer all questions in Section B. Write your answers in the spaces provided. Answer any two questions in Section C. All essential working should be shown. For numerical answers, unit should be quoted wherever appropriate. Begin each answer on a fresh sheet of paper and arrange your answers in numerical order. Arahan kepada calon:

JANGAN BUKA KERTAS SOALAN INI SEHINGGA ANDA DIBENARKAN BERBUAT DEMIKIAN. Jawab semua soalan dalam Bahagian A. Markah tidak akan ditolak bagi jawapan yang salah. Bagi setiap soalan, empat cadangan jawapan diberikan. Pilih jawapan yang betul dan buat bulatan pada jawapan tersebut. Jawab semua soalan dalam Bahagian B. Tulis jawapan anda di ruang yang diberikan. Jawab mana-mana dua soalan dalam Bahagian C. Semua jalan kerja yang sesuai hendaklah ditunjukkan. Bagi jawapan berangka, unit hendaklah dinyatakan di mana-mana yang sesuai. Mulakan setiap jawapan pada helaian kertas jawapan yang baharu dan susun jawapan anda mengikut tertib berangka.

This question paper consists of printed pages and blank page. (Kertas soalan ini terdiri daripada halaman bercetak dan halaman kosong.)

© Majlis Peperiksaan Malaysia STPM 962/1

42

Section A [15 marks]

Answer all questions in this section. 1 Which particle has the correct corresponding number of electrons and number of neutrons?

Particle Number of electrons Number of neutrons

A N167 9 7

B −2188 O 8 10

C F199 19 9

D +Br7935 34 44

2 The mass spectrum of an element X is shown below. From the mass spectrum above, it can be concluded that,

A the nucleon number of X is 14.5

B the relative molecular mass of X2 is 29

C the isotopes of X have a different number of protons

D element X consists of two isotopes with relative isotopic mass of 14 and 15 3 What is the maximum number of emission lines possible for a hydrogen atom with electronic energy levels n = 1, n = 2 and n = 3?

A 2 B 3 C 4 D 6 4 Which compound is not ionic?

A CaCl2 B SiCl4 C Al2O3 D Mg3N2 5 Which molecule possesses polar bonds but its overall molecular dipole moment is zero?

A NH3 B H2S C CCl4 D CH3Cl 962/1

100 − 99.63

14 15 Mass/charge 0

Percentage of abundance

0.37

43

Bahagian A [15 markah]

Jawab semua soalan dalam bahagian ini. 1 Zarah yang manakah yang mempunyai padanan yang betul dengan nombor elektron dan nombor neutron?

Zarah Nombor elektron Nombor neutron

A N167 9 7

B −2188 O 8 10

C F199 19 9

D +Br7935 34 44

2 Spektrum jisim unsur X ditunjukkan di bawah. Daripada spektrum jisim di atas, dapat disimpulkan bahawa

A nombor nukleon X ialah 14.5

B jisim molekul relatif X2 ialah 29

C isotop X mempunyai nombor proton yang berbeza

D unsur X terdiri daripada dua isotop dengan jisim isotop relatif 14 dan 15 3 Berapakah bilangan garisan pemancaran maksimum yang mungkin bagi atom hidrogen dengan aras tenaga elektronik n = 1, n = 2, dan n = 3?

A 2 B 3 C 4 D 6 4 Sebatian yang manakah yang tidak ionik?

A CaCl2 B SiCl4 C Al2O3 D Mg3N2 5 Molekul yang manakah yang mempunyai ikatan berkutub tetapi jumlah momen dwikutubnya molekulnya adalah sifar? A NH3 B H2S C CCl4 D CH3Cl 962/1

100 − 99.63

14 15 Jisim/cas 0

Peratusan kelimpahan

0.37

44

6 Which statement regarding metallic bond is correct?

A The metallic bond enables metals to be a good conductor of heat.

B The strength of the metallic bond depends on the size of the atom of the metal.

C The metallic bonds are formed because metals have relatively high ionisation energies.

D The metallic bond is formed from the attraction between the electrons and the nucleus in the atom.

7 A mixture of 8.0 g of a monoatomic gas X and an unknown quantity of mass of diatomic gas Y has a volume of V m3 at s.t.p. When 20.0 g of gas X is added to the mixture under the same conditions, the volume of the mixture is 2V m3. What is the quantity of gas Y in the mixture?

[Relative atomic masses of X and Y are 4 and 1 respectively. Assume that gas X does not react with gas Y.]

A 1 g B 2 g C 5 g D 6 g 8 Boron nitride, BN, can exist in two different forms P and Q. P has a layered giant molecular lattice with weak forces between the layers. Q has a giant lattice in which each atom is bonded to another by four covalent bonds. The following statements are regarding P and Q.

I P and Q have high melting points.

II P and Q have the same density.

III Structure Q is harder than structure P.

IV Structure Q conducts electricity in molten state.

Which statements about P and Q are correct?

A I and II

B I and III

C II and IV

D III and IV 962/1

45

6 Penyataan yang manakah yang betul tentang ikatan logam?

A Ikatan logam membolehkan logam menjadi konduksi haba yang baik.

B Kekuatan ikatan logam bergantung kepada saiz atom logam itu.

C Ikatan logam yang terbentuk disebabkan logam mempunyai tenaga pengionan yang tinggi secara relatifnya.

D Ikatan logam terbentuk daripada penarikan antara elektron dengan nuklues dalam atom. 7 Satu campuran 8.0 g gas monoatom X dan satu kuantiti gas dwiatom Y yang tidak diketahui jisimnya mempunyai isi padu V m3 pada s.t.p. Apabila 20.0 g gas X ditambahkan kepada campuran itu pada keadaan yang sama, isi padu campuran itu ialah 2V m3. Berapakah kuantiti gas Y dalam campuran itu?

[Jisim atom relatif bagi X dan Y masing-masing ialah 4 dan 1. Anggap bahawa gas X tidak bertindak balas dengan gas Y.]

A 1 g B 2 g C 5 g D 6 g 8 Boron nitrida, BN, boleh wujud dalam dua bentuk yang berbeza, P dan Q. P mempunyai lapisan kekisi molekul raksasa dengan daya yang lemah antara lapisan. Q mempunyai kekisi raksasa yang mana setiap atom terikat kepada atom yang lain oleh empat ikatan kovalen. Penyataan yang berikut berkaitan dengan P dan Q.

I P dan Q mepunyai takat lebur yang tinggi

II P dan Q mempunyai ketumpatan yang sama

III Struktur Q lebih keras daripada struktur P

IV Struktur Q mengkonduksi elektik dalam keadaan leburan

Penyataan yang manakah yang betul tentang P dan Q?

A I dan II

B I dan III

C II dan IV

D III dan IV 962/1

46

9 The distribution of molecular kinetic energy of a gas at 279 K and 289 K is shown by the Maxwell-BØltzman graph below.

Which statement best explains why the rate of reaction in a gas sample at 279 K increases two folds when the temperature is increased to 289 K?

A The number of collisions increases two fold.

B The total area under the curve increases two fold.

C The average velocity of the molecules increases two fold.

D The numbers of molecules with energy equal to or greater than Ea increases two fold.

10 The Arrhenius equation is given as k = .aE

RTAe−

A reaction occurs 27 times faster at 52 °C than at 22 °C. What is the activation energy for this reaction?

[Gas constant, R, is 8.31 J K−1 mol−1]

A 1.04 kJ mol−1 B 10.5 kJ mol−1 C 38.1 kJ mol−1 D 87.5 kJ mol−1 11 A reversible reaction can be represented by the equation:

P + Q R + S

when the system is in equilibrium,

A the masses P, Q, R and S are the same

B the reactions in both directions stopped

C the concentrations of P, Q, R and S are the same

D the concentrations of P, Q, R and S are always constant 12 The equilibrium constant, Kp, for the decomposition of calcium carbonate,

CaCO3(s) CaO(s) + CO2(g)

is 1.6 × 10−23 atm at 298 K and 6.3 × 10−11 atm at 500 K. Which statement is true of the decomposition?

A The forward reaction is endothermic.

B Kp depends on the mass of CaCO3 used.

C The rate of forward reaction decreases as the temperature increases.

D The activation energy of forward reaction increases as the temperature increases. 962/1

Kinetic energy

Number of molecules

47

9 Taburan tenaga kinetik bagi gas pada 279 K dan 289 K ditunjukkan dalam graf Maxwell-BØltzman di bawah.

Penyataan yang manakah yang paling baik menerangkan mengapa kadar tindak balas dalam sampel gas pada 279 K bertambah dua kali ganda apabila suhu dinaikkan kepada 289 K?

A Bilangan perlanggaran bertambah dua kali ganda.

B Jumlah luas kawasan di bawah lengkung bertambah dua kali ganda.

C Halaju purata molekul bertambah dua kali ganda.

D Bilangan molekul dengan tenaga yang sama atau lebih besar daripada Ea bertambah dua kali ganda.

10 Persamaan Arrhenius diberikan sebagai k = .aE

RTAe−

Satu tindak balas berlaku 27 lebih cepat pada 52 °C berbanding 22 °C. Berapakah tenaga pengaktifan bagi tindak balas ini?

[Pemalar gas, R ialah 8.31 J K−1 mol−1]

A 1.04 kJ mol−1 B 10.5 kJ mol−1 C 38.1 kJ mol−1 D 87.5 kJ mol−1 11 Suatu tindak balas berbalik boleh diwakili dengan persamaan:

P + Q R + S

apabila sistem itu dalam keadaan keseimbangan,

A jisim P, Q, R, dan S adalah sama

B tindak balas dalam kedua-dua arah dihentikan

C kepekatan P, Q, R, dan S adalah sama

D kepekatan P, Q, R, dan S sentiasa malar 12 Pemalar keseimbangan, Kp, bagi penguraian kalsium karbonat,

CaCO3(p) CaO(p) + CO2(g)

ialah 1.6 × 10−23 atm pada 298 K dan 6.3 × 10−11 atm pada 500 K. Penyataan yang manakah yang betul tentang penguraian itu?

A Tindak balas ke hadapan adalah endotermik.

B Kp bergantung pada jisim CaCO3 yang digunakan.

C Kadar tindak balas ke hadapan berkurang apabila suhu bertambah.

D Tenaga pengaktifan bagi tindak balas ke hadapan bertambah apabila suhu bertambah. 962/1

Tenaga kinetik

Bilangan molekul

48

13 In the reaction Cu2+ + 4NH3 [Cu(NH3)4]2+, the Cu2+ ion acts as a

A Lewis acid

B Lewis base

C BrØnsted-Lowry acid

D BrØnsted-Lowry base 14 The following quantities may change when 0.10 mol dm−3 ethanoic acid is diluted with water at 298 K.

I Acid dissociation constant

II pH value

III Degree of dissociation

IV Ionic product of water Which quantities will change?

A I and II

B I and IV

C II and III

D III and IV 15 The graph below shows the variation of pH for the titration of 25.0 cm3 of 0.2 mol dm−3 aqueous ammonia solution with 0.2 mol dm−3 hydrochloric acid.

Which part of the above graph shows the mixture of ammonia and hydrochloric acid that can be used as buffer solution?

A p B q C r D s

962/1

Volume of HCl added/cm3

pH

49

13 Dalam tindak balas, Cu2+ + 4NH3 [Cu(NH3)4]2+, ion Cu2+ bertindak sebagai

A asid Lewis

B bes Lewis

C asid BrØnsted-Lowry

D bes BrØnsted-Lowry 14 Kuantiti yang berikut boleh berubah apabila asid etanoik 0.10 mol dm−3 dicairkan dengan air pada 298 K.

I Pemalar penceraian asid

II Nilai pH

III Darjah penceraian

IV Hasil darab ion bagi air Kuantiti yang manakah yang akan berubah?

A I dan II

B I dan IV

C II dan III

D III dan IV 15 Graf di bawah menunjukkan ubahan pH bagi pentitratan 25.0 cm3 larutan akueus ammonia 0.2 mol dm−3 dengan asid hidroklorik 0.2 mol dm−3.

Bahagian yang manakah pada graf di atas yang menunjukkan campuran ammonia dan asid hidroklorik boleh digunakan sebagai larutan penimbal?

A p B q C r D s 962/1

Isi padu HCl ditambah/cm3

pH

50

Section B [15 marks]

Answer all questions in this section. 16 Beams of particles from different sources are passed through an electric field. The path of the beam of sub-atomic particles Y through the electric field is shown in the diagram below.

(a) (i) Name the subatomic particles Y. [1 mark] .................................................................................................................................................................... (ii) Draw the paths of the beams of electrons and hydrogen ions in the above diagram. [2 marks] (iii) If a beam of deuterium ions is passed through the electric field, explain the difference in deflection angle between the beam of hydrogens ions and that of deuterium ions. [2 marks] .................................................................................................................................................................... .................................................................................................................................................................... (b) P+ and Q– ions are isoelectronic with the 40

18 X isotope.

(i) State the nucleon number of the 4018 X isotope. [1 mark]

.................................................................................................................................................................... (ii) Identity P+ and Q– ions. [2 marks] .................................................................................................................................................................... ....................................................................................................................................................................

962/1

+

Source of particles –

51

Bahagian B [15 markah]

Jawab semua soalan dalam bahagian ini. 16 Alur-alur zarah dari sumber-sumber yang berlainan dilalukan menerusi suatu medan elektrik. Laluan alur zarah subatom Y menerusi medan elektrik ditunjukkan dalam gambar rajah di bawah. (a) (i) Namakan zarah subatom Y itu. [1 markah] .................................................................................................................................................................... (ii) Lukis laluan alur elektron dan ion hidrogen pada gambar rajah di atas. [2 markah] (iii) Jika alur ion deuterium dilalukan melalui medan elektrik tersebut, jelaskan perbezaan sudut pesongan antara alur ion hidrogen dengan alur ion deuterium. [2 markah] .................................................................................................................................................................... .................................................................................................................................................................... (b) Ion P+ and ion Q– adalah isoelektronik dengan isotop 40

18 .X

(i) Nyatakan nombor nukleon bagi isotop 4018 .X [1 markah]

.................................................................................................................................................................... (ii) Kenal pasti ion P+ dan ion Q–. [2 markah] .................................................................................................................................................................... .................................................................................................................................................................... 962/1

+

Sumber zarah –

52

17 The table below shows the temperature and pressure of critical point and triple point of substance X.

Temperature/°C Pressure/atm

Critical point 31 73

Triple point –57 5 At atmospheric pressure, X sublimes at –78 °C. The freezing point of X increases by 2 °C for every 10 atm increase in pressure.

(a) Using the above information, sketch and label the phase diagram of X. [4 marks] (b) Why does the freezing point of X increase with pressure? [1 mark] .................................................................................................................................................................... (c) Solid X is known as dry ice.

(i) How is liquid X produced from dry ice? [1 mark] .................................................................................................................................................................... (ii) State an industrial use for dry ice. [1 mark] ....................................................................................................................................................................

962/1

53

17 Jadual di bawah menunjukkan suhu dan tekanan bagi takat genting dan takat ganda tiga bahan X.

Suhu/°C Tekanan/atm

Takat genting 31 73

Takat ganda tiga –57 5 Pada tekanan atmosfera, X memejalwap pada suhu –78 °C. Takat beku X bertambah sebanyak 2 °C bagi setiap pertambahan tekanan 10 atm.

(a) Menggunakan maklumat di atas, lakar dan label gambar rajah fasa X. [4 markah] (b) Mengapakah takat beku X bertambah dengan tekanan? [1 markah] .................................................................................................................................................................... (c) Pepejal X dikenal sebagai ais kering.

(i) Bagaimanakah cecair X dihasilkan daripada ais kering? [1 markah] .................................................................................................................................................................... (ii) Nyatakan satu kegunaan industri ais kering. [1 markah] .................................................................................................................................................................... 962/1

54

Section C [30 marks]

Answer any two questions in this section. 18 (a) Water is a hydride of oxygen. The bonding in water molecules is a result of the overlapping of the orbitals of oxygen and hydrogen atoms.

(i) What is meant by orbitals? [1 mark]

(ii) Draw a labelled diagram illustrating the shapes of all the orbitals of an oxygen atom with quantum number n = 2. [3 marks]

(iii) Draw a labelled diagram to illustrate the overlapping of orbitals in a water molecule. [3 marks]

(b) Draw the Lewis structures for ion I3−

and molecule SF6, and state their geometries. [4 marks]

State why

(i) compound SF6 is used as an insulating gas in high voltage electrical appliances,

[1 mark]

(ii) compound SI6 does not exist, [1 mark]

(iii) I3− and Br3

− ions exist but F3− ion does not exist under normal conditions. [2 marks]

19 Aqueous chlorine dioxide solution reacts with an alkaline solution according to the following equation.

2ClO2(aq) + 2OH−(aq) ClO3−(aq) + ClO2

−(aq) + H2O(l)

(a) Determine the oxidation number of chlorine in ClO2 and ClO3−. [2 marks]

(b) The results of the kinetic experiment of the reaction of aqueous chlorine dioxide solution are shown in the table below.

Experiment number

[ClO2]/ mol dm−3

[OH−]/ mol dm−3

Initial rate/ mol dm−3 s−1

1 0.0575 0.0216 8.21 × 10−3

2 0.0713 0.0216 1.26 × 10−2

3 0.0575 0.0333 1.26 × 10−2 (i) Determine the order of the reaction. [7 marks]

(ii) Calculate the rate constant, k, for the reaction. [2 marks]

(iii) Calculate the pH of the aqueous chlorine dioxide solution, if its concentration is 0.100 mol dm−3 and the initial rate of the disproportionation reaction is 3.56 × 10−2 mol dm−3 s−1. [4 marks] 962/1

55

Bahagian C [30 markah]

Jawab mana-mana dua soalan dalam bahagian ini. 18 (a) Air ialah hidrida oksigen. Ikatan dalam molekul air terhasil melalui pertindihan orbital atom oksigen dengan atom hidrogen.

(i) Apakah yang dimaksudkan dengan orbital? [1 markah]

(ii) Lukis gambar rajah berlabel yang mengilustrasikan bentuk semua orbital bagi atom oksigen dengan nombor kuantum n = 2. [3 markah]

(iii) Lukis gambar rajah berlabel untuk mengilustrasi pertindihan orbital dalam molekul air. [3 markah]

(b) Lukis struktur Lewis bagi ion I3−

dan molekul SF6, dan nyatakan geometri bagi ion I3−

dan molekul SF6. [4 markah]

Nyatakan mengapa

(i) sebatian SF6 digunakan sebagai gas penebat dalam alat-alat elektrik bervoltan tinggi,

[1 markah]

(ii) sebatian SI6 tidak wujud, [1 markah]

(iii) ion I3− dan ion Br3

− wujud tetapi ion F3− tidak wujud dalam keadaan biasa. [2 markah]

19 Larutan klorin dioksida akueus bertindak balas dengan larutan beralkali mengikut persamaan yang berikut.

2ClO2(ak) + 2OH−(ak) ClO3−(ak) + ClO2

−(ak) + H2O(c)

(a) Tentukan nombor pengoksidaan klorin dalam ClO2 dan ClO3−. [2 markah]

(b) Keputusan uji kaji kinetik dalam tindak balas larutan akueus klorin dioksida ditunjukkan dalam jadual di bawah.

Nombor uji kaji

[ClO2]/ mol dm−3

[OH−]/ mol dm−3

Kadar awal/ mol dm−3 s−1

1 0.0575 0.0216 8.21 × 10−3

2 0.0713 0.0216 1.26 × 10−2

3 0.0575 0.0333 1.26 × 10−2 (i) Tentukan tertib tindak balas itu. [7 markah]

(ii) Hitung pemalar kadar, k, bagi tindak balas itu. [2 markah]

(iii) Hitung pH larutan akueus klorin dioksida, jika kepekatannya ialah 0.100 mol dm−3 dan kadar awal tindak balas penyahkadarannya ialah 3.56 × 10−2 mol dm−3 s−1. [4 markah] 962/1

56

20 (a) The Haber process is used in the industrial production of ammonia. The equation for the reaction is as follows.

N2(g) + 3H2(g) 2NH3(g) ΔH°= −92 kJ mol−1

An analysis of an equilibrium mixture obtained from the mixing of gaseous nitrogen and hydrogen shows a composition of 40% of ammonia when the total pressure of the system is 20 atm.

(i) Determine the mole fraction of nitrogen, hydrogen and ammonia. [3 marks]

(ii) Calculate the partial pressures for nitrogen, hydrogen and ammonia. [2 marks]

(iii) Calculate the equilibrium constant, Kp, for the equilibrium. [2 marks]

(b) In an experiment, 0.100 moles of dinitrogen tetraoxide gas is allowed to dissociate to nitrogen dioxide gas in a 1.0 dm3 container at 383 K. The graph of concentrations of both gases against time is shown below.

(i) Calculate the equilibrium constant, Kc, for the above reaction at 383 K. [4 marks] (ii) Calculate the pressure in the container after the system had attained equilibrium at 383 K. [4 marks]

[Gas constant, R, is 8.31 J K−1 mol−1.] 962/1

Time/min

Concentration/ mol dm−3

57

20 (a) Proses Haber digunakan dalam penghasilan industri ammonia. Persamaan bagi tindak balas adalah seperti yang berikut.

N2(g) + 3H2(g) 2NH3(g) ΔH°= −92 kJ mol−1

Analisis suatu campuran keseimbangan yang diperoleh daripada campuran gas nitrogen dan hidrogen menunjukkan komposisi ammonia 40% apabila jumlah tekanan sistem adalah 20 atm.

(i) Tentukan pecahan mol nitrogen, hidrogen, dan ammonia. [3 markah]

(ii) Hitung tekanan separa bagi nitrogen, hidrogen, dan ammonia. [2 markah]

(iii) Hitung pemalar keseimbangan, Kp, untuk keseimbangan itu. [2 markah]

(b) Dalam satu uji kaji, 0.100 mol gas dinitrogen tetraoksida dibiarkan tercerai kepada gas nitrogen dioksida di dalam bekas 1.0 dm3 pada 383 K. Graf kepekatan kedua-dua gas itu lawan masa ditunjukkan di bawah.

(i) Hitung pemalar keseimbangan, Kc, bagi tindak balas di atas pada 383 K. [4 markah] (ii) Hitung tekanan dalam bekas selepas sistem mencapai keseimbangan pada 383 K. [4 markah]

[Pemalar gas, R, ialah 8.31 J K−1 mol−1.] 962/1

Masa/min

Kepekatan/ mol dm−3


59

SPECIMEN PAPER

962/2 STPM

CHEMISTRY (KIMIA)

PAPER 2 (KERTAS 2)









60


Answer all questions in this section. 1 Which equation represents the enthalpy of atomisation of sodium?

A Na(s) → Na(g)

B Na(l) → Na(g)

C Na(l) → Na+(g) + e−

D Na(g) → Na+(g) + e− 2 The diagram below shows the Born-Haber cycle for the formation of sodium fluoride.

Na(s) + ½F2(g) NaF(s) +107 kJ mol−1 +79 kJ mol−1 Na(g) F(g) −928 kJ mol−1

+496 kJ mol−1 Na+(g) + F

−(g) What is the electron affinity of fluorine?

A −820 kJ mol−1 B −328 kJ mol−1 C −275 kJ mol−1 D −246 kJ mol−1 3 Which cation has the highest hydration energy?

A Li+ B Na+ C K+ D Rb+ 962/2

−574 kJ mol−1

61


Jawab semua soalan dalam bahagian ini. 1 Persamaan yang manakah yang mewakili entalpi pengatoman natrium?

A Na(p) → Na(g)

B Na(c) → Na(g)

C Na(c) → Na+(g) + e−

D Na(g) → Na+(g) + e− 2 Gambar rajah di bawah menunjukkan kitar Born-Haber bagi pembentukan natrium fluorida.

Na(p) + ½F2(g) NaF(p) +107 kJ mol−1 +79 kJ mol−1 Na(g) F(g) −928 kJ mol−1

+496 kJ mol−1 Na+(g) + F

−(g) Berapakah afiniti elektron fluorin?

A −820 kJ mol−1 B −328 kJ mol−1 C −275 kJ mol−1 D −246 kJ mol−1 3 Kation yang manakah yang mempunyai tenaga penghidratan paling tinggi?

A Li+ B Na+ C K+ D Rb+ 962/2

−574 kJ mol−1

62

4 The standard reduction potentials, E °, for oxygen and manganese are as follows.

Electrode system E °/V

O2(g), H+(aq), H2O2(aq)⎪Pt(s) +0.68

MnO4−(aq), H+(aq), Mn2+(aq)⎪Pt(s) +1.52

The chemical cell constructed by combining the two half-cells above may have the following results.

I Mn2+ ion undergoes reduction to form MnO4− ion.

II H2O2 undergoes oxidation to form O2.

III The platinum electrode for oxygen half-cell is the positive electrode.

IV The e.m.f. of the cell is +0.84 V.

Which of the above statements are true for the chemical cell formed?

A I and II

B I and III

C II and IV

D III and IV 5 The graph below shows the standard reduction potentials, E°, for the half-cell reactions of five elements, P, Q, R, S and T.

It can be concluded that from P to T,

A the electronegativity of the elements increases

B the chemical reactivity of the elements decreases

C the strength of the elements as reducing agents increases

D the strength of the elements as oxidising agents increases 962/2

E°/V

Element

63

4 Keupayaan penurunan piawai, E °, bagi oksigen dan mangan adalah seperti yang berikut.

Sistem elektrod E °/V

O2(g), H+(ak), H2O2(ak)⎪Pt(p) +0.68

MnO4−(ak), H+(ak), Mn2+(ak)⎪Pt(p) +1.52

Sel kimia yang dibina daripada gabungan dua setengah sel di atas mungkin mempunyai keputusan yang berikut.

I Ion Mn2+ mengalami penurunan untuk membentuk ion MnO4− .

II H2O2 mengalami pengoksidaan untuk membentuk O2.

III Elektrod platinum bagi setengah sel oksigen ialah elektrod positif.

IV D.g.e. sel ialah +0.84 V.

Penyataan di atas yang manakah yang benar bagi sel kimia yang terbentuk?

A I dan II

B I dan III

C II dan IV

D III dan IV 5 Graf di bawah menunjukkan keupayaan penurunan piawai, E°, bagi tindak balas setengah sel lima unsur, P, Q, R, S, dan T.

Dapat disimpulkan bahawa daripada P hingga T,

A keelektronegatifan unsur-unsur bertambah

B kereaktifan kimia unsur-unsur berkurang

C kekuatan unsur-unsur sebagai agen penurunan bertambah

D kekuatan unsur-unsur sebagai agen pengoksidaan bertambah 962/2

E°/V

Unsur

64

6 The standard reduction potentials, E°, for several copper and iron species are given below.

Electrode system E°/V

Cu2+(aq)/Cu+(aq) +0.15

Cu2+(aq)/Cu(s) +0.34

Cu+(aq)/Cu(s) +0.52

Fe2+(aq)/Fe(s) −0.44

Fe3+(aq)/Fe(s) −0.04

Fe3+(aq)/Fe2+(aq) +0.77

Which statement regarding the species is correct?

A Cu(s) is the strongest reducing agent.

B Fe3+(aq) is the strongest oxidising agent.

C Cu2+(aq) is able to oxidise Fe2+(aq) to Fe3+(aq).

D The e.m.f. of the cell Fe(s)⏐Fe2+(aq) Cu+(aq)⏐Cu(s) is 0.08 V. 7 A molten compound consisting of the elements X and Y is electrolysed using a current of 1.00 A for 1930 seconds. 2.07 g of X is formed at the cathode and 1.60 g of Y is formed at the anode. What is the correct empirical formula for the compound?

[Relative atomic masses for X and Y are 207.0 and 80.0 respectively; Faraday’s constant, F, is 96 500 C mol−1.]

A XY B XY2 C X2Y D X2Y2 8 Across Period 3 of the Periodic Table, from sodium to chlorine

A the electronegativity of the elements decreases

B the ionisation energy of the elements decreases

C the standard reduction potential of the elements increases

D the strength of the elements as reducing agents increases 9 The solubilities of two sulphates of Group 2 elements in the Periodic Table are given below.

Compound Solubility (g per 100 g) at 20 °C

CaSO4 2.3 × 10−1

BaSO4 2.3 × 10−4

Which statement best explains the above data?

A The size of Ba2+ ion is bigger than that of Ca2+ ion.

B Barium has a lower ionisation energy than calcium.

C BaSO4 has a lower lattice energy than CaSO4.

D Ba2+ ion has a lower hydration energy than Ca2+ ion. 962/2

65

6 Keupayaan penurunan piawai, E°, bagi beberapa spesis kuprum dan ferum diberikan di bawah.

Sistem elektrod E°/V

Cu2+(ak)/Cu+(ak) +0.15

Cu2+(ak)/Cu(p) +0.34

Cu+(ak)/Cu(p) +0.52

Fe2+(ak)/Fe(p) −0.44

Fe3+(ak)/Fe(p) −0.04

Fe3+(ak)/Fe2+(ak) +0.77

Penyataan yang manakah yang betul tentang spesis itu?

A Cu(p) ialah agen penurunan yang paling kuat.

B Fe3+(ak) ialah agen pengoksidaan yang paling kuat.

C Cu2+(ak) boleh mengoksida Fe2+(ak) kepada Fe3+(ak).

D D.g.e sel Fe(p)⏐Fe2+(ak) Cu+(ak)⏐Cu(p) ialah 0.08 V. 7 Satu sebatian lebur yang terdiri daripada unsur X dan Y telah dielektrolisiskan menggunakan arus 1.00 A selama 1930 saat. Sebanyak 2.07 g X terbentuk di katod dan 1.60 g Y terbentuk di anod. Apakah formula empirik yang betul bagi sebatian itu?

[Jisim atom relatif bagi X dan Y masing-masing ialah 207.0 dan 80.0; Pemalar Faraday, F, ialah 96 500 C mol−1.]

A XY B XY2 C X2Y D X2Y2 8 Merentasi Kala 3 Jadual Berkala, daripada natrium ke klorin

A keelektronegatifan unsur berkurang

B tenaga pengionan unsur berkurang

C keupayaan penurunan piawai unsur bertambah

D kekuatan unsur sebagai agen penurunan bertambah 9 Keterlarutan dua sulfat unsur Kumpulan 2 dalam Jadual Berkala diberikan di bawah.

Sebatian Keterlarutan (g per 100 g) pada 20 °C

CaSO4 2.3 × 10−1

BaSO4 2.3 × 10−4

Penyataan yang manakah yang paling tepat menjelaskan data di atas?

A Saiz ion Ba2+ lebih besar daripada ion Ca2+.

B Barium mempunyai tenaga pengionan yang lebih rendah daripada kalsium.

C BaSO4 mempunyai tenaga kekisi yang lebih rendah daripada CaSO4.

D Ion Ba2+ mempunyai tenaga penghidratan lebih rendah daripada ion Ca2+. 962/2

66

10 A tetrachloride of Group 14, XCl4, of the Periodic Table is thermally unstable and easily hydrolysed. It decomposes at room temperature according the equation:

XCl4 → XCl2 + Cl2

What is X ?

A Carbon B Silicon C Germanium D Lead 11 Which statement is true of the oxides of Group 14 elements of the Periodic Table?

A All the oxides have covalent bonds.

B The oxides with +4 oxidation state can react with alkalis.

C The oxides with +4 oxidation state are more stable down the group.

D The acidity of the oxides with +2 oxidation state increases down the group. 12 An aqueous solution of X, a mixture of two compounds, has the following properties.

(i) Decomposes in the presence of light to form a gas.

(ii) Reacts with aqueous barium hydroxide to form salt and water.

(iii) Reacts with aqueous silver nitrate to form a precipitate which can dissolve in aqueous ammonia.

The following compounds may be found in an aqueous solution of X.

I HCl

II HBr III HOCl IV NH4Cl What could X be?

A I and II

B I and III

C II and IV

D III and IV 13 Halogens or their compounds are not used

A as detergents

B in photography

C as propellant in aerosol

D in the sterilisation of water 962/2

67

10 Satu tetraklorida Kumpulan 14, XCl4, Jadual Berkala tidak stabil secara terma dan mudah terhidrolisis. Tetraklorida itu terurai pada suhu bilik mengikut persamaan:

XCl4 → XCl2 + Cl2

Apakah X ?

A Karbon B Silikon C Germanium D Plumbum 11 Penyataan yang manakah yang benar tentang oksida unsur Kumpulan 14 Jadual Berkala?

A Kesemua oksida mempunyai ikatan kovalen.

B Oksida dengan keadaan pengoksidaan +4 boleh bertindak balas dengan alkali.

C Oksida dengan keadaan pengoksidaan +4 lebih stabil apabila menuruni kumpulan.

D Keasidan oksida dengan keadaan pengoksidaan +2 bertambah apabila menuruni kumpulan. 12 Satu larutan akueus X, suatu campuran dua sebatian, mempunyai sifat-sifat yang berikut.

(i) Terurai dalam kehadiran cahaya untuk membentuk gas.

(ii) Bertindak balas dengan akueus barium hidroksida untuk membentuk garam dan air.

(iii) Bertindak balas dengan akueus argentum nitrat untuk membentuk mendakan yang melarut dalam ammonia akueus.

Sebatian yang berikut mungkin terdapat dalam larutan akueus X.

I HCl

II HBr III HOCl IV NH4Cl Apakah X ?

A I dan II

B I dan III

C II dan IV

D III dan IV 13 Halogen atau sebatiannya tidak digunakan

A sebagai detergen

B dalam fotografi

C sebagai propelan dalam aerosol

D dalam pensterilan air 962/2

68

14 In which compound does the transition element have the lowest oxidation state?

A NH4VO3

B K3Fe(CN)6

C CrO2Cl2

D MnC2O4 15 A transition element can act as a homogeneous catalyst because

A it exhibits variable oxidation states

B it decreases the enthalpy of reactions

C it supplies energy to increase the rate of effective collisions

D it supplies electrons to facilitate adsorption through the formation of temporary bonds 962/2

69

14 Sebatian yang manakah unsur peralihannya mempunyai keadaan pengoksidaan paling rendah?

A NH4VO3

B K3Fe(CN)6

C CrO2Cl2

D MnC2O4 15 Unsur peralihan boleh bertindak sebagai mangkin homogen kerana

A unsur peralihan mempamerkan keadaan pengoksidaan yang berubah

B unsur peralihan mengurangkan entalpi tindak balas

C unsur peralihan membekalkan tenaga untuk menambah kadar perlanggaran efektif

D unsur peralihan membekalkan elektron untuk memudahkan penjerapan melalui pembentukan ikatan sementara.

962/2

70


Answer all questions in this section. 16 (a) The two common oxides of lead are lead(II) oxide and lead(IV) oxide. Lead(II) oxide dissolves readily in aqueous nitric acid. Lead(IV) oxide reacts with concentrated hydrochloric acid to form lead(II) chloride and chlorine.

(i) Write a balanced equation for the reaction between lead(II) oxide and aqueous nitric acid. [1 mark] .................................................................................................................................................................... (ii) What is the property shown by lead(II) oxide in the reaction in part (i)? [1 mark] .................................................................................................................................................................... (iii) Write a balanced equation for the reaction between lead(IV) oxide and concentrated hydrochloric acid. [1 mark] .................................................................................................................................................................... (iv) State the change in the oxidation number of lead in the reaction in part (iii). [1 mark] .................................................................................................................................................................... (v) What is the property shown by lead(IV) oxide in this reaction? [1 mark] ................................................................................................................................................................... (vi) State the relative stability of lead(II) and lead(IV) compounds. [1 mark] ................................................................................................................................................................... (b) PbCl4 is a liquid at room temperature and undergoes hydrolysis.

(i) State the geometrical shape of PbCl4. [1 mark] .................................................................................................................................................................... (ii) Why does PbCl4 undergo hydrolysis? [1 mark] .................................................................................................................................................................... 962/2

71


Jawab semua soalan dalam bahagian ini. 16 (a) Dua oksida plumbum yang lazim ialah plumbum(II) oksida dan plumbum(IV) oksida. Plumbum(II) oksida melarut dengan mudah dalam asid nitrik akueus. Plumbum(IV) oksida bertindak balas dengan asid hidroklorik pekat untuk membentuk plumbum(II) klorida dan klorin.

(i) Tulis persamaan berimbang bagi tindak balas antara plumbum(II) oksida dengan asid nitrik akueus. [1 markah] .................................................................................................................................................................... (ii) Apakah sifat yang ditunjukkan oleh plumbum(II) oksida dalam tindak balas pada bahagian (i)? [1 markah] .................................................................................................................................................................... (iii) Tulis persamaan berimbang bagi tindak balas antara plumbum(IV) oksida dengan asid hdroklorik pekat. [1 markah] .................................................................................................................................................................... (iv) Nyatakan perubahan nombor pengoksidaan plumbum dalam tindak balas pada bahagian (iii). [1 markah] .................................................................................................................................................................... (v) Apakah sifat yang ditunjukkan oleh plumbum(IV) oksida dalam tindak balas ini? [1 markah] ................................................................................................................................................................... (vi) Nyatakan kestabilan relatif sebatian plumbum(II) dan sebatian plumbum(IV). [1 markah] ................................................................................................................................................................... (b) PbCl4 adalah cecair pada suhu bilik dan mengalami hidrolisis.

(i) Nyatakan bentuk geometri PbCl4. [1 markah] .................................................................................................................................................................... (ii) Mengapakah PbCl4 mengalami hidrolisis? [1 markah] .................................................................................................................................................................... 962/2

72

17 (a) A bleach liquid can be prepared from the reaction of chlorine with aqueous solution of sodium hydroxide at room temperature.

(i) Write a balanced ionic equation for the reaction that occurs. [1 mark] .................................................................................................................................................................... (ii) State the change in oxidation state of chlorine in the reaction. [1 mark] .................................................................................................................................................................... (iii) State the active substance of bleaching liquid formed. [1 mark] .................................................................................................................................................................... (b) Photochromic glass is made based on the concept of black-white photography.

(i) What is the additive substance of photochromic glass? [1 mark] .................................................................................................................................................................... (ii) State what happens when photochromic glass is exposed to light, and write a balanced equation for the reaction. [3 marks] .................................................................................................................................................................... .................................................................................................................................................................... Equation:....................................................................................................................................................

962/2

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17 (a) Satu cecair peluntur boleh disediakan daripada tindak balas klorin dengan larutan akueus natrium hidroksida pada suhu bilik.

(i) Tulis persamaan berimbang bagi tindak balas yang berlaku. [1 markah] .................................................................................................................................................................... (ii) Nyatakan perubahan keadaan pengoksidaan klorin dalam tindak balas itu. [1 markah] .................................................................................................................................................................... (iii) Nyatakan bahan aktif cecair peluntur yang terbentuk. [1 markah] .................................................................................................................................................................... (b) Kaca fotokromik dibuat berdasarkan konsep fotografi hitam putih.

(i) Apakah bahan tambahan kaca fotokromik? [1 markah] .................................................................................................................................................................... (ii) Nyatakan apakah yang berlaku apabila kaca fotokromik terdedah kepada cahaya, dan tulis persamaan berimbang bagi tindak balas itu. [3 markah] .................................................................................................................................................................... .................................................................................................................................................................... Persamaan:................................................................................................................................................

962/2

74


Answer any two questions in this section. 18 (a) Liquid hydrazine, N2H4, is used as a rocket fuel because its enthalpy of combustion is highly exothermic. The thermochemical equation for the combustion of hydrazine is as follows:

N2H4(1) + O2(g) → N2(g) + 2H2O(g) ΔH = –534.0 kJ

(i) In an experiment, 1.0 g of hydrazine is burnt in a bomb calorimeter. Calculate the temperature change if the total heat capacity of the bomb calorimeter and its contents is 5.86 kJ °C–1. [5 marks]

(ii) The enthalpy of formation of water vapour is –242.0 kJ mol–1. Calculate the enthalpy of formation of hydrazine. [3 marks]

(b) The enthalpies of vaporisation of the sodium, aluminium and chlorine are given in the table below.

Element Enthalpy of vaporisation/kJ mol–1

Sodium 103

Aluminium 294

Chlorine 20.4 (i) Explain the variations in the enthalpies of vaporisation of sodium, aluminium and chlorine. [4 marks]

(ii) Sodium and aluminium react separately with chlorine to form sodium chloride and aluminium chloride respectively. Which of these compounds has a higher enthalpy of vaporisation? Justify your answer. [3 marks] 19 Explain the variations of the following properties on descending Group 2 of the Periodic Table. Write equations where appropriate.

(a) First ionisation energy of the elements. [5 marks]

(b) Reactivity of the elements towards water. [5 marks]

(c) Thermal stability of their nitrates. [5 marks]

962/2

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Jawab mana-mana dua soalan dalam bahagian ini. 18 (a) Cecair hidrazina, N2H4, digunakan sebagai bahan api roket kerana entalpi pembakarannya sangat eksotermik. Persamaan termokimia bagi pembakaran hidrazina adalah seperti yang berikut:

N2H4(c) + O2(g) → N2(g) + 2H2O(g) ΔH = –534.0 kJ

(i) Dalam satu uji kaji, 1.0 g hidrazina dibakar dalam kalorimeter bom. Hitung perubahan suhu jika jumlah muatan haba kalorimeter bom dan kandungannya itu ialah 5.86 kJ °C–1. [5 markah]

(ii) Entalpi pembentukan wap air ialah –242.0 kJ mol–1. Hitung entalpi pembentukan hidrazina. [3 markah]

(b) Entalpi pengewapan natrium, aluminium, dan klorin diberikan dalam jadual di bawah.

Unsur Entalpi pengewapan /kJ mol–1

Natrium 103

Aluminium 294

Klorin 20.4 (i) Jelaskan perubahan entalpi pengewapan natrium, aluminium, dan klorin. [4 markah]

(ii) Natrium dan aluminium masing-masing bertindak balas secara berasingan dengan klorin untuk membentuk natrium klorida dan aluminium klorida. Sebatian tersebut yang manakah yang mempunyai entalpi pegewapan paling tinggi? Justifikasikan jawapan anda. [3 markah] 19 Jelaskan ubahan sifat yang berikut apabila menuruni Kumpulan 2 Jadual Berkala. Tulis persamaan di mana-mana yang sesuai.

(a) Tenaga pengionan pertama unsur. [5 markah]

(b) Kereaktifan unsur terhadap air. [5 markah]

(c) Kestabilan terma nitratnya. [5 markah] 962/2

76

20 (a) The common oxidation states of the transition metal ions below are +2 and +3. The graph below shows the trend in standard reduction potentials of M

3+(aq)/M 2+(aq) system of selected transition metal ions.

(i) Name two ions that have stable +2 oxidation state in aqueous solution. Justify your answer. [3 marks]

(ii) The standard reduction potentials, E°, of several species are given below.

Reaction E°/V

Fe2+ + 2e− Fe −0.44

Fe3+ + 3e− Fe −0.04

Fe3+ + 3e− Fe2+ +1.77

O2 + 4H+ + 4e− 2H2O +1.23

O2 + 2H2O + 4e− 4OH− +0.40

O2 + 2H+ + 2e− H2O2 +0.68

Using the appropriate E° values, explain why an aqueous solution of iron(II) ions changes from pale green to yellow when exposed to air. [6 marks]

(b) (i) Name the complex ions [Ni(NH2CH2CH2NH2)3]2+ and [Ni(CN)4]2− according to IUPAC nomenclature. [2 marks]

(ii) Aqueous nickel(II) chloride reacts with aqueous ammonia to form a precipitate X. X dissolves in excess aqueous ammonia to form a solution Y. Write the equations for the reactions that occur, and state the colours of X and Y. [4 marks] 962/2

Standard electrode potential /V

77

20 (a) Keadaan pengoksidaan lazim bagi ion logam peralihan di bawah ialah +2 dan +3. Graf di bawah menunjukkan trend keupayaan penurunan piawai bagi sistem M

3+(ak)/M 2+(ak) bagi ion logam peralihan yang terpilih.

(i) Namakan dua ion yang mempunyai keadaan pengoksidaan +2 yang stabil dalam larutan akueus. Justifikasikan jawapan anda. [3 markah]

(ii) Keupayaan penurunan piawai, E°, bagi beberapa spesis diberikan di bawah.

Tindak balas E°/V

Fe2+ + 2e− Fe −0.44

Fe3+ + 3e− Fe −0.04

Fe3+ + 3e− Fe2+ +1.77

O2 + 4H+ + 4e− 2H2O +1.23

O2 + 2H2O + 4e− 4OH− +0.40

O2 + 2H+ + 2e− H2O2 +0.68

Dengan menggunakan nilai E° yang bersesuaian, jelaskan mengapa larutan akueus ion ferum(II) berubah daripada hijau pucat kepada kuning apabila terdedah ke udara. [6 markah]

(b) (i) Namakan ion kompleks [Ni(NH2CH2CH2NH2)3]2+ dan ion kompleks [Ni(CN)4]2− mengikut tatanama IUPAC. [2 markah]

(ii) Nikel(II) klorida akueus bertindak balas dengan ammonia akueus untuk membentuk mendakan X. X melarut dalam ammonia akueus berlebihan untuk membentuk larutan Y. Tulis persamaan bagi tindak balas yang berlaku, dan nyatakan warna X dan Y. [4 markah] 962/2

Keupayaan elektrod piawai /V


79

SPECIMEN PAPER

962/3 STPM

CHEMISTRY (KIMIA)

PAPER 3 (KERTAS 3)









80


Answer all questions in this section. 1 Which compound has a carbon atom that exhibits sp3 hybridisation?

A CH2=CH−CH=CH2

B

C

D H−C≡C−H 2 When 0.1 mol of hydrocarbon X is burnt in excess oxygen, 17.6 g carbon dioxide is produced. 0.1 mol of X is found to react with 4.48 dm3 of bromine vapour under standard conditions. What is the possible structural formula of X ?

[Relative atomic massess of C and O are 12.0 and 16.0 respectively ; the molar volume of a gas is 22.4 dm3 at stp.]

A CH3CH=CHCH3

B CH2=C=C=CH2

C CH3CH2CH2CH3

D CH2=CHCH=CH2 3 Which compound shows optical isomerism?

A CH3CH=CHCH3

B CH3CH2C(Cl)2CH3

C CH3CH2CH(OH)CH3

D HOCH2CH(OH)CH2OH 4 Which reaction involves an electrophilic reagent?

A CH3CH3 + Cl2 → CH3CH2Cl + HCl

B CH3Br + NaOH → CH3OH + NaBr

C CH3CH=CH2 + HBr → CH3CHBrCH3

D CH3COOH + CH3CH2OH → CH3COOCH2CH3 + H2O 5 A mixture of excess ethane and chlorine is exposed to light. What is the major product of the reaction?

A Cl3CCH3

B ClCH2CH3

C Cl2CHCH3

D Cl2CHCHCl2 962/3

CH=CH2

CH3

81


Jawab semua soalan dalam bahagian ini. 1 Sebatian yang manakah yang mempunyai atom karbon yang menunjukkan penghibridan sp3?

A CH2=CH−CH=CH2

B

C

D H−C≡C−H 2 Apabila 0.1 mol hidrokarbon X dibakar dalam oksigen berlebihan, 17.6 g karbon dioksida dihasilkan. Didapati bahawa 0.1 mol X akan bertindak balas dengan 4.48 dm3 wap bromin dalam keadaan piawai. Apakah formula struktur yang mungkin bagi X ?

[Jisim atom relatif bagi C dan O masing-masing ialah 12.0 dan 16.0; isi padu molar gas ialah 22.4 dm3 pada stp.]

A CH3CH=CHCH3

B CH2=C=C=CH2

C CH3CH2CH2CH3

D CH2=CHCH=CH2 3 Sebatian yang manakah yang menunjukkan isomer optik?

A CH3CH=CHCH3

B CH3CH2C(Cl)2CH3

C CH3CH2CH(OH)CH3

D HOCH2CH(OH)CH2OH 4 Tindak balas yang manakah yang melibatkan reagen elektrofilik?

A CH3CH3 + Cl2 → CH3CH2Cl + HCl

B CH3Br + NaOH → CH3OH + NaBr

C CH3CH=CH2 + HBr → CH3CHBrCH3

D CH3COOH + CH3CH2OH → CH3COOCH2CH3 + H2O 5 Satu campuran etana yang berlebihan dan klorin terdedah kepada cahaya. Apakah hasil utama tindak balas itu?

A Cl3CCH3

B ClCH2CH3

C Cl2CHCH3

D Cl2CHCHCl2 962/3

CH=CH2

CH3

82

6 An organic compound Z undergoes a catalytic hydrogenation reaction. Z also reacts with hydrogen bromide to form 2-bromopropane.

The structural formula of Z is

A CH3CH2CH3

B CH2=CH2

C CH3CH=CH2

D CH3CH(OH)CH3 7 The following statements are about nitration of benzene.

I Nitric acid acts as an electrophile.

II The reaction involves free radicals.

III Nitronium ion, NO2+, is an electrophile.

IV Nitronium ion, NO2+, is formed from concentrated H2SO4 and HNO3.

Which statements regarding the mechanism of nitration of benzene are true?

A I and II

B I and IV

C II and III

D III and IV 8 Which reaction occurs through SN1 mechanism?

A C6H5CH2Br + NH3 ⎯→ C6H5CH2NH2 + HBr

B (CH3)3CBr + NaOH ⎯→ (CH3)3COH + NaBr

C CH3CHBrCH3 + KCN ⎯→ CH3CH(CN)CH3 + KBr

D CH3CH2CH2Br + KOH ⎯→ CH3CH2CH2OH + KBr 9 When an optically active compound Z is heated with chromic acid, the product formed is not optically active but react with alkaline iodine. Compound Z could be

A (CH3)2CHCH2OH

B CH3CH2CH(OH)CH2CH3

C CH3CH2CH2CH(OH)CH3

D ⎯ CH(OH)CH2CH3

10 Compound X is oxidised to compound Y. Y does not reduce Fehling’s solution. X could be

A CH3CH2CH2OH

B CH3CHOHCH3

C (CH3)3COH

D CH3COCH3 962/3

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6 Satu sebatian organik Z mengalami tindak balas penghidrogenan bermangkin. Z juga bertindak balas dengan hidrogen bromida untuk membentuk 2-bromopropana.

Formula struktur Z ialah

A CH3CH2CH3

B CH2=CH2

C CH3CH=CH2

D CH3CH(OH)CH3 7 Penyataan yang berikut adalah tentang penitratan benzena.

I Asid nitrik bertindak sebagai elektrofil.

II Tindak balas melibatkan radikal bebas.

III Ion nitronium, NO2+ ialah elektrofil.

IV Ion nitronium, NO2+, terbentuk daripada H2SO4 pekat dan HNO3.

Penyataan yang manakah yang betul berkaitan dengan mekanisme penitratan benzena?

A I dan II

B I dan IV

C II dan III

D III dan IV 8 Tindak balas yang manakah yang berlaku melalui mekanisme SN1?

A C6H5CH2Br + NH3 ⎯→ C6H5CH2NH2 + HBr

B (CH3)3CBr + NaOH ⎯→ (CH3)3COH + NaBr

C CH3CHBrCH3 + KCN ⎯→ CH3CH(CN)CH3 + KBr

D CH3CH2CH2Br + KOH ⎯→ CH3CH2CH2OH + KBr 9 Apabila sebatian Z yang aktif optik dipanaskan dengan asid kromik, hasil yang terbentuk tidak aktif optik tetapi bertindak balas dengan iodin beralkali. Sebatian Z mungkin

A (CH3)2CHCH2OH

B CH3CH2CH(OH)CH2CH3

C CH3CH2CH2CH(OH)CH3

D ⎯ CH(OH)CH2CH3

10 Sebatian X dioksidakan kepada sebatian Y. Y tidak menurunkan larutan Fehling’s. X mungkin

A CH3CH2CH2OH

B CH3CHOHCH3

C (CH3)3COH

D CH3COCH3

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11 Which compound produces a yellow precipitate when reacts with 2,4-dinitrophenylhydrazine?

A CH3CH2CH2C−OH

B CH3CH2C−OCH3

C CH3CH2CH2C−Cl

D CH3CH2CCH3 12 Phenol is used to prepare CH3COOC6H5 through an intermediate X as shown in the following scheme.

C6H5OH ⎯⎯⎯⎯→ X ⎯⎯⎯⎯→ CH3COOC6H5

What are reagent I and reagent II in the above scheme?

Reagent I Reagent II

A Na CH3COCl

B PCl5 CH3COCl

C PCl5 CH3COOH

D NaOH CH3COOH 13 An amine is produced in a two-step reaction as shown below.

2-Bromopropane ⎯⎯⎯⎯⎯→ ⎯⎯⎯⎯⎯→ Amine What is the structural formula of this amine? A CH3CH2CH2CH2NH2 B CH3CH2CH(CH3)NH2 C (CH3)2CHCH2NH2 D CH3CH(NH2)CH3 14 The structural formula of a peptide is as follows.

The peptide is

A a dipeptide

B a tripeptide

C a neutral compound

D an acidic compound 962/3

KCN/ethanol Na/ethanol

Reagent I Reagent II

H2N CH

CH2OH

C OH N

H CH3

CH C N

H

CH C

CH2CH2CH2NH2

OOO

O

O

O

O

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11 Sebatian yang manakah yang menghasilkan mendakan kuning apabila bertindak balas dengan 2,4-dinitrofenilhidrazina?

A CH3CH2CH2C−OH

B CH3CH2C−OCH3

C CH3CH2CH2C−Cl

D CH3CH2CCH3 12 Fenol digunakan untuk menyediakan CH3COOC6H5 melalui perantaraan X seperti ditunjukkan dalam skema yang berikut.

C6H5OH ⎯⎯⎯⎯→ X ⎯⎯⎯⎯→ CH3COOC6H5

Apakah reagen I dan reagen II dalam skema di atas?

Reagen I Reagen II

A Na CH3COCl

B PCl5 CH3COCl

C PCl5 CH3COOH

D NaOH CH3COOH 13 Suatu amina dihasilkan dalam dua langkah tindak balas seperti ditunjukkan di bawah.

2-Bromopropana ⎯⎯⎯⎯⎯→ ⎯⎯⎯⎯⎯→ Amina

Apakah formula struktur amina ini? A CH3CH2CH2CH2NH2 B CH3CH2CH(CH3)NH2 C (CH3)2CHCH2NH2 D CH3CH(NH2)CH3 14 Formula struktur suatu peptida adalah seperti yang berikut.

Peptida itu ialah

A dipeptida

B tripeptida

C sebatian neutral

D sebatian berasid 962/3

KCN/etanol Na/etanol

Reagen I Reagen II

O

O

O

O

H2N CH

CH2OH

C OH N

H CH3

CH C N

H

CH C

CH2CH2CH2NH2

OOO

86

15 The following is a pair of a polymer and its possible repeating unit.

Polymer Repeating unit

I Poly(propene) ⎯ CH(CH3)CH2 ⎯

II Poly(styrene) ⎯ CHCH2CHCH2 ⎯

III Terylene ⎯ OCH2CH2OCO

IV Nylon-6,6 ⎯ CO(CH2)5NH ⎯

Which is the correct match between a polymer and its repeating unit?

A I and II

B I and IV

C II and III

D III and IV 962/3

⎯ CO ⎯

87

15 Padanan yang berikut adalah tentang polimer dan unit ulangan yang mungkin.

Polimer Unit ulangan

I Poli(propena) ⎯ CH(CH3)CH2 ⎯

II Poli(stirena) ⎯ CHCH2CHCH2 ⎯

III Terilena ⎯ OCH2CH2OCO

IV Nilon-6,6 ⎯ CO(CH2)5NH ⎯

Padanan yang manakah yang betul antara polimer dan unit ulangannya?

A I dan II

B I dan IV

C II dan III

D III dan IV

962/3

⎯ CO ⎯

88


Answer all questions in this section. 16 (a) Starting with 1-bromopropane, CH3CH2CH2Br, show the reaction schemes to synthesise the following carboxylic acids. [4 marks]

(i) CH3CH2COOH (ii) CH3CH2CH2COOH (b) Write equations for the reactions between benzoyl chloride, C6H5COCl, and the following compounds, and name the organic products according to the IUPAC nomenclature. [4 marks]

(i) CH3NH2 (ii) C6H5OH 962/3

89


Jawab semua soalan dalam bahagian ini. 16 (a) Bermula dengan 1-bromopropana, CH3CH2CH2Br, tunjukkan skema tindak balas untuk mensintesiskan asid karboksilik yang berikut. [4 markah]

(i) CH3CH2COOH (ii) CH3CH2CH2COOH (b) Tulis persamaan bagi tindak balas antara benzoil klorida, C6H5COCl, dengan sebatian yang berikut, dan namakan hasil-hasil organik itu mengikut tatanama IUPAC. [4 markah]

(i) CH3NH2 (ii) C6H5OH 962/3

90

17 (a) Compound X is a phenylalanine which is an essential amino acid that must be provided in the diet for healthy growth. The structural formula of X is given below. (i) Name the functional groups in compound X. [2 marks] .................................................................................................................................................................... .................................................................................................................................................................... (ii) Draw the structure of X at isoelectric point. State the direction of the movement of X when a potential difference is applied to an aqueous solution of X at isoelectric point. [2 marks] (iii) Draw the structure of X at pH = 2. [1 mark] (iv) Draw the structure of dipeptide formed from two molecules of X. [1 mark] (v) Name the lingkage in the dipeptide. [1 mark] .................................................................................................................................................................... 962/3

CH2 CHCOOH

NH2

91

17 (a) Sebatian X ialah fenilalanina yang merupakan asid amino perlu disediakan dalam diet untuk pertumbuhan yang sihat. Formula struktur X diberikan di bawah. (i) Namakan kumpulan berfungsi dalam sebatian X. [2 markah] .................................................................................................................................................................... .................................................................................................................................................................... (ii) Lukis struktur X pada takat isoelektrik. Nyatakan arah gerakan X apabila satu beza keupayaan dikenakan pada larutan akueus X pada takat isoelektrik. [2 markah] (iii) Lukis struktur X pada pH = 2. [1 markah] (iv) Lukis struktur dipeptida yang terbentuk daripada dua molekul X. [1 markah] (v) Namakan rangkaian dalam dipeptida itu. [1 markah] .................................................................................................................................................................... 962/3

CH2 CHCOOH

NH2

92


Answer any two questions in this section. 18 (a) Methylbenzene is obtained from benzene using Friedel-Crafts reaction.

(i) State the reagent and conditions required for the reaction. [2 marks]

(ii) Write a balanced equation for the reaction. [1 mark]

(iii) State the electrophile involved in this reaction. [1 mark]

(iv) Describe a simple chemical test to detect the presence of methylbenzene. Write an equation for the reaction involved. [3 marks]

(b) Chlorine gas is bubbled into methylbenzene in the presence of light and in the absence of a catalyst.

(i) Draw structural formulae of any two organic compounds formed and name them. [4 marks]

(ii) Write the mechanism for the reaction. [4 marks] 19 The table below lists the acid dissociation constants, Ka, for three hydroxy compounds in aqueous solutions at 298 K.

Name of compound Formula Ka/mol dm−3

Cyclohexanol 1.0 × 10−18

Phenol 1.0 × 10−10

4-Methylphenol 6.8 × 10−11

(a) Arrange the three compounds above in the order of increasing acidity. Justify your answer. [7 marks]

(b) Describe a chemical test to differentiate the acidity between cyclohexanol and phenol. [4 marks]

(c) State the reagents and reaction conditions in the oxidation and bromination of 4-methylphenol, and draw the structural formula of the products formed. [4 marks] 962/3

OH

OH

H3C OH

93


Jawab mana-mana dua soalan dalam bahagian ini. 18 (a) Metilbenzena diperoleh daripada benzena menggunakan tindak balas Friedel-Crafts.

(i) Nyatakan reagen dan keadaan yang diperlukan bagi tindak balas itu. [2 markah]

(ii) Tulis persamaan berimbang bagi tindak balas itu. [1 markah]

(iii) Nyatakan elektrofil yang terlibat dalam tindak balas tersebut. [1 markah]

(iv) Perihalkan satu ujian kimia ringkas untuk mengesan kehadiran metilbenzena. Tulis persamaan bagi tindak balas yang terlibat. [3 markah]

(b) Gas klorin dilalugelembungkan ke dalam metilbenzena dalam kehadiran cahaya dan dalam ketakhadiran mangkin.

(i) Lukis formula struktur mana-mana dua sebatian organik yang terbentuk dan namakannya. [4 markah]

(ii) Tulis mekanisme bagi tindak balas itu. [4 markah] 19 Jadual di bawah menyenaraikan pemalar penceraian asid, Ka, bagi tiga sebatian hidroksi dalam larutan akueus pada 298 K.

Nama sebatian Formula Ka/mol dm−3

Sikloheksanol 1.0 × 10−18

Fenol 1.0 × 10−10

4-Metilfenol 6.8 × 10−11

(a) Susun tiga sebatian di atas mengikut tertib menaik keasidannya. Justifikasikan jawapan anda. [7 markah]

(b) Perihalkan satu ujian kimia untuk membezakan keasidan antara sikloheksanol dengan fenol. [4 markah]

(c) Nyatakan reagen dan keadaan tindak balas dalam pengoksidaan dan pembrominan 4-metilfenol, dan lukis formula struktur hasil yang terbentuk. [4 markah]

962/3

OH

OH

H3C OH

94

20 A monobasic carboxylic acid Z has the following composition by mass: carbon, 54.5%; hydrogen, 9.1%; and oxygen, 36.4%. Titration of 0.10 g of Z requires 11.40 cm3 of 0.100 mol dm−3 sodium hyroxide for complete neutralisation. Z can be synthesised from -propanol by a three-step reaction as shown below.

CH3CH2CH2OH ⎯→ X ⎯→ Y ⎯⎯→ Z (a) Determine the empirical and molecular formulae of Z. [6 marks]

(b) State the reagents and the conditions required in each of the steps. [3 marks]

(c) Draw the structural formulae of X, Y and Z. [3 marks]

(d) A mixture of -propanol and Z is refluxed with concentrated sulphuric acid. Name the reaction and the organic product formed, and write a balanced equation for the reaction involved. [3 marks]

[Relative atomic masses of H, C and O are 1.0, 12.0 and 16.0 respectively.] 962/3

I II III

1

1

95

20 Satu asid karboksilik monobes Z mempunyai komposisi mengikut jisim: karbon, 54.5%; hidrogen, 9.1%; dan oxigen, 36.4%. Pentitratan 0.10 g Z memerlukan 11.40 cm3 natrium hidroksida 0.100 mol dm−3 untuk peneutralan lengkap. Z dapat disintesiskan daripada -propanol melalui tiga langkah tindak balas seperti ditunjukkan di bawah.

CH3CH2CH2OH ⎯→ X ⎯→ Y ⎯⎯→ Z (a) Tentukan formula empirik dan formula molekul Z. [6 markah]

(b) Nyatakan reagen dan keadaan yang diperlukan dalam setiap langkah itu. [3 markah]

(c) Lukis formula struktur X, Y, dan Z. [3 markah]

(d) Satu campuran -propanol dan Z direfluks dengan asid sulfurik pekat. Namakan tindak balas dan hasil organik yang terbentuk, dan tulis persamaan berimbang bagi tindak balas yang terlibat. [3 markah]

[Jisim atom relatif bagi H, C, dan O masing-masing ialah 1.0, 12.0, dan 16.0.]

962/3

I II III

1

1

97

SPECIMEN EXPERIMENT

962/4 STPM

CHEMISTRY

PAPER 4




STPM CHEMISTRY STUDENT’S MANUAL 20___/20___

98

Topic : Thermochemistry Purpose : To determine the heat of neutralisation of a strong acid with a strong base Materials : KA 1 is 1.0 mol dm-3 hydrochloric acid.

KA 2 is a 1.0 mol dm-3 solution of a strong acid W.

KA 3 is 1.0 mol dm-3 aqueous sodium hydroxide.

KA 4 is 1.0 mol dm-3 nitric acid.

KA 5 is 1.0 mol dm-3 aqueous potassium hydroxide. Procedure : (a) By means of a pipette, place 10.0 cm3 of KA 1 into a plastic cup. Record the

temperature of KA 1 as the initial temperature of mixture X in the table below.

By means of a measuring cylinder, add 30 cm3 of solution KA 3 into the plastic cup containing KA 1. Stir mixture X carefully with a thermometer and record the highest temperature attained in the table below. Pour away mixture X from the plastic cup. Then clean and rinse the cup with distilled water.

Repeat the above procedure using

(i) 10.0 cm3 of KA 2 to replace KA 1 to obtain mixture Y, and

(ii) 10.0 cm3 of KA 4 and 30 cm3 of KA 5 to replace KA 1 and KA 3 respectively to obtain mixture Z.

Results : (b) Complete the table below.

Mixture X KA 1 + KA 3

Mixture Y KA 2 + KA 3

Mixture Z KA 4 + KA 5

Highest temperature/°C

Initial temperature/°C

Increase in temperature/°C

Questions : (c) If 4.2 Joules is required to raise the temperature by 1 °C for 1 cm3 of solution,

calculate the heat released for each of the experiments conducted. (d) Calculate the number of moles of the following solutions added into the plastic

cup.

(i) Sodium hydroxide

(ii) Potassium hydroxide

(iii) Hydrochloric acid

(iv) Nitric acid

(v) Acid W 962/4

STPM CHEMISTRY STUDENT’S MANUAL 20___/20___

99

(e) Write an ionic equation for the reaction taking place in mixtures X, Y, and Z. (f) Calculate the heat of neutralisation for each reaction. (g) (i) Explain why the values of the heat of neutralisation you obtained differ in

mixtures X, Y, and Z.

(ii) The heat of neutralisation between a strong acid and a strong base is −57.3 kJ mol−1. How would you improve the given procedure so that an approximate value of −57.3 kJ mol−1 could be obtained?

962/4


101

SPECIMEN PAPER

962/5 STPM

CHEMISTRY (KIMIA)

PAPER 5 (KERTAS 5)




Instructions to candidates: DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE TOLD TO DO SO. Answer all questions. All working should be shown. Numerical answers should be given to an appropriate number of significat figures or decimal places, units should be quoted where appropriate.

For your calculations, use the following relative atomic masses:

H = 1.0; Mn = 54.9; N = 14.0; C = 12.0; O = 16.0; K = 39.1. Arahan kepada calon: JANGAN BUKA KERTAS SOALAN INI SEHINGGA ANDA DIBENARKAN BERBUAT DEMIKIAN. Jawab semua soalan. Semua kerja hendaklah ditunjukkan. Jawapan berangka hendaklah diberikan hingga bilangan angka bererti atau tempat perpuluhan yang sesuai, unit hendaklah dinyatakan di mana-mana yang sesuai.

Untuk penghitungan anda, gunakan jisim atom relatif yang berikut:

H = 1.0; Mn = 54.9; N = 14.0; C = 12.0; O = 16.0; K = 39.1.



102

1 An experiment was carried out to determine the percentage of ammonium ethanedioate, (NH4)2C2O4, in a mixture of two ethanedioate salts.

An aqueous solution of X was prepared by dissolving a mixture of (NH4)2C2O4 and KHC2O4 in distilled water.

(a) In this experiment, 25.0 cm3 of the aqueous solution of X was pipetted into a titration flask followed by 25 cm3 of sulphuric acid and then heated to a temperature of approximately 60 oC. The aqueous solution of X was then titrated with 0.02 mol dm−3 aqueous solution of potassium manganate(VII) . The reactions involved are shown by the following equation.

2MnO4−(aq) + 5C2O4

2− (aq) + 16H+(aq) 2Mn2+(aq) + 10CO2 (g) + 8H2O(l)

(i) State the steps taken in transferring 25.0 cm3 of the aqueous solution of X into the titration flask by using a pipette. [3 marks] …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… (ii) The burette readings for the rough and accurate titrations are shown in the table below. Complete the table. [1 mark]

Accurate Titration Rough

First Second Third

Final reading/cm3 30.0 30.75 30.05 30.90

Initial reading/cm3 1.1 2.20 1.30 2.20

Volume of KMnO4 aqueous solution/cm3 28.9

(iii) By showing the suitable values of titres chosen, calculate the average titre value. [2 marks]

962/5

103

1 Satu uji kaji telah dijalankan untuk menentukan peratusan ammonium etanadioat, (NH4)2C2O4, dalam satu campuran dua garam etanadioat.

Larutan akueus X disediakan dengan melarutkan campuran (NH4)2C2O4 dan KHC2O4 dalam air suling.

(a) Dalam uji kaji ini, 25.0 cm3 larutan akueus X dipipetkan ke dalam kelalang pentitratan diikuti 25 cm3 asid sulfurik dan kemudian dipanaskan ke suhu lebih kurang 60 °C. Larutan akues X kemudian dititratkan dengan larutan akues kalium manganat(VII) 0.02 mol dm−3. Tindak balas yang terlibat ditunjukkan dengan persamaan yang berikut.

2MnO4−(ak) + 5C2O4

2− (ak) + 16H+(ak) 2Mn2+(ak) + 10CO2 (g) + 8H2O(c)

(i) Nyatakan langkah-langkah yang diambil untuk memindahkan 25.0 cm3 larutan akueus X ke dalam kelalang pentitratan dengan menggunakan sebuah pipet. [3 markah] …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… (ii) Bacaan buret bagi pentitratan kasar dan jitu ditunjukkan dalam jadual di bawah. Lengkapkan jadual ini. [1 markah]

Jitu Pentitratan Kasar

Pertama Kedua Ketiga

Bacaan akhir/cm3 30.0 30.75 30.05 30.90

Bacaan awal/cm3 1.1 2.20 1.30 2.20

Isi padu larutan akueus KMnO4 /cm3 28.9

(iii) Hitung nilai purata titer dengan menunjukkan nilai-nilai titer yang sesuai digunakan. [2 markah] 962/5

104

(iv) Calculate the concentration, in mol dm−3, of ethanedioate ions C2O42− in the aqueous

solution of X. [2 marks] (v) Name a suitable apparatus used to measure 25 cm3 of sulphuric acid. [1 mark] …………………………………………………………………………………………………………… (b) When 25.0 cm3 of the aqueous solution of X was titrated with 0.05 mol dm−3 aqueous solution of sodium hydroxide using a suitable indicator, it was found that 12.40 cm3 of aqueous solution of sodium hydroxide was needed for a complete reaction.

(i) State a suitable indicator used for this titration. [1 mark] …………………………………………………………………………………………………………… (ii) State the colour of the solution at the end point of the titration. [1 mark] …………………………………………………………………………………………………………… (iii) Calculate the concentration, in mol dm−3, of KHC2O4 in the aqueous solution of X. [2 marks] (iv) Calculate the percentage by mass of (NH4)2C2O4 in the aqueous solution of X.

[2 marks] 962/5

105

(iv) Hitung kepekatan, dalam mol dm−3, ion etanadioat C2O42− dalam larutan akueus X.

[2 markah] (v) Namakan alat radas yang sesuai digunakan untuk menyukat 25 cm3 asid sulfurik. [1 markah] …………………………………………………………………………………………………………… (b) Apabila 25.0 cm3 larutan akueus X dititratkan dengan larutan akueus natrium hidroksida 0.05 mol dm−3 dengan menggunakan penunjuk yang sesuai, didapati bahawa 12.40 cm3 larutan akueus natrium hidroksida diperlukan bagi tindak balas lengkap.

(i) Nyatakan penunjuk yang sesuai digunakan dalam penitratan ini. [1 markah] …………………………………………………………………………………………………………… (ii) Nyatakan warna larutan pada takat akhir penitratan. [1 markah] …………………………………………………………………………………………………………… (iii) Hitung kepekatan, dalam mol dm−3, KHC2O4 dalam larutan akueus X. [2 markah] (iv) Hitung peratusan mengikut jisim (NH4)2C2O4 dalam larutan akueus X. [2 markah] 962/5

106

2 An experiment is carried out to investigate the effect of temperature on the rate of reaction.

In the experiment, 50.0 cm3 of 0.10 mol dm−3 hydrogen peroxide solution and 20.0 cm3 of 1.0 mol dm−3 sulphuric acid are added into a conical flask containing 25.0 cm3 of 0.15 mol dm−3 potassium iodide solution, 10.0 cm3 of 0.050 mol dm−3 sodium thiosulphate solution and 10.0 cm3 of 0.5% starch solution.

(a) The duration from the instant hydrogen peroxide solution is added to the mixture until the appearance of the blue colouration at different temperatures is recorded in the table below.

Complete the table. [1 mark]

Temperature T/°C 18.0 28.0 38.0 48.0

Time t/s 73.0 49.0 36.0 25.0

1t

/s–1

(i) Name a suitable apparatus used to measure 50.0 cm3 of hydrogen peroxide solution. [1 mark] …………………………………………………………………………………………………………… (ii) What causes the blue colouration? [1 mark] …………………………………………………………………………………………………………… (iii) Write the equation for the reaction between hydrogen peroxide and potassium iodide. [1 mark] ……………………………………………………………………………………………………………

(iv) What is the relationship between the rate of reaction and 1t

? [1 mark]

…………………………………………………………………………………………………………… 962/5

107

2 Satu uji kaji telah dijalankan untuk mengkaji kesan suhu terhadap kadar tindak balas.

Dalam uji kaji itu, 50.0 cm3 larutan hidrogen peroksida 0.10 mol dm−3 dan 20.0 cm3 asid sulfurik 1.0 mol dm−3 ditambahkan ke dalam satu kelalang kon yang mengandung 25.0 cm3 larutan kalium iodida 0.15 mol dm−3, 10.0 cm3 larutan natrium tiosulfat 0.050 mol dm−3, dan 10.0 cm3 larutan kanji 0.5%.

(a) Tempoh masa dari ketika larutan hidrogen peroksida ditambahkan ke dalam campuran sehingga kewujudan warna biru larutan pada suhu yang berlainan direkodkan dalam jadual di bawah.

Lengkapkan jadual ini. [1 markah]

Suhu T/°C 18.0 28.0 38.0 48.0

Masa t/s 73.0 49.0 36.0 25.0

1t

/s–1

(i) Namakan alat radas yang sesuai digunakan untuk menyukat 50.0 cm3 larutan hidrogen peroksida. [1 markah] …………………………………………………………………………………………………………… (ii) Apakah yang menyebabkan warna biru larutan? [1 markah] …………………………………………………………………………………………………………… (iii) Tulis persamaan bagi tindak balas antara hidrogen peroksida dengan kalium iodida. [1 markah] ……………………………………………………………………………………………………………

(iv) Apakah hubungan antara kadar tindak balas dengan 1t

? [1 markah]

…………………………………………………………………………………………………………… 962/5

108

(b) Plot a graph of 1t

against T. [2 marks]

962/5

109

(b) Plot graf 1t

lawan T. [2 markah]

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110

(c) Based on the graph,

(i) state the effect of temperature on the rate of reaction. [1 mark] …………………………………………………………...…………………………………..…………... (ii) compare the rates of the reaction at 30 °C and 40 °C. Explain your answer. [2 marks] …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... (d) Describe a method to determine the appearance of the blue colouration. [2 marks] …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... (e) Suggest an experiment to study the effect of concentration of hydrogen peroxide on the rate of reaction. [3 marks] …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... 962/5

111

(c) Berdasarkan graf itu,

(i) nyatakan kesan suhu terhadap kadar tindak balas. [1 markah] …………………………………………………………...…………………………………..…………... (ii) bandingkan kadar tindak balas pada 30 °C dan 40 °C. Jelaskan jawapan anda. [2 markah] …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... (d) Perihalkan kaedah untuk menentukan kemunculan warna biru larutan. [2 markah] …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... (e) Cadangkan satu uji kaji untuk mengkaji kesan kepekatan hidrogen peroksida terhadap kadar tindak balas. [3 markah] …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... …………………………………………………………...…………………………………..…………... 962/5

112

3 When water is added to a white solid U, a solution containing Al3+, NH4+ and SO4

2− ions is obtained. The scheme below shows some observations obtained when certain reagents are added to the white solid U and its aqueous solution.

(a) What is the colour of an aqueous solution of U? [1 mark] …………………………………………………………...…………………………………..…………... Using Appendix A and Appendix B, answer the following questions. (b) State the observations (i), (ii), (iii), (iv), (v) and (vi). [6 marks] (i) ……….…………………………………………………………………………………… (ii) ……………….…………………………………………………………………………… (iii) ……….…………………………………………………………………………………… (iv) ……….…………………………………………………………………………………… (v) ……….…………………………………………………………………………………… (vi) ……….…………………………………………………………………………………… 962/5

(iv) White solid U

Aqueous solution of U

White precipitate

Colourless solution

White precipitate

Gas W

(i)

(ii)

White fumes

Na2CO3(aq)

Water

Pb(NO3)2(aq) NH3(aq)

Ba(NO3)2(aq)

Dilute HNO3

K2CrO4(aq)

NaOH(aq)

Excess NaOH(aq)

Gas Z

Gases X and Y

Nessler reagent

II

I

Δ

Δ

(iii) (v)

Colourless solution

(iv)

113

3 Apabila air ditambahkan kepada satu pepejal putih, U, satu larutan mengandung ion Al3+, ion NH4

+ dan ion SO42− diperoleh. Skema di bawah menunjukkan beberapa pemerhatian yang diperoleh

apabila reagen tertentu ditambahkan kepada pepejal putih U dan larutan akueusnya.

(a) Apakah warna larutan akueus U? [1 markah] …………………………………………………………...…………………………………..…………... Dengan menggunakan Lampiran A dan Lampiran B, jawab soalan yang berikut. (b) Nyatakan pemerhatian (i), (ii), (iii), (iv), (v), dan (vi). [6 markah] (i) ……….…………………………………………………………………………………… (ii) ……………….…………………………………………………………………………… (iii) ……….…………………………………………………………………………………… (iv) ……….…………………………………………………………………………………… (v) ……….…………………………………………………………………………………… (vi) ……….…………………………………………………………………………………… 962/5

(iv) Pepejal putih U

Larutan akueus U

Mendakan putih

Larutan tak berwarna

Mendakan putih

Gas W

(i)

(ii)

Wasap putih

Na2CO3(ak)

Air

Pb(NO3)2(ak) NH3(ak)

Ba(NO3)2(ak)

HNO3 cair

K2CrO4(ak)

NaOH(ak)

NaOH(ak) berlebihan

Gas Z

Gas X dan gas Y

Reagen Nessler

II

I

Δ

Δ

(iii) (v)

Larutan tak berwarna

(iv)

114

(c) Name the gases W, X, Y and Z. [4 marks] W:….……………………………………………………………….……………………..……............... X:………………………………………………………………….……………………..………………. Y:………………………………………………………………….………………..……………………. Z: ………………………………………………………………….………………..…………................ (d) Name the reagents I and II, and state the conditions where appropriate. [2 marks] I: …………………………………………………………………………………………..……………..

II:………………………………………………………………………………………………………… (e) Describe a method to test gas W. [2 marks] ……………………………………………………………………………………………..……………..

....………………………………………………………………………………………………………… 962/5

115

(c) Namakan gas W, X, Y, dan Z. [4 markah] W:….……………………………………………………………….……………………..……............... X:………………………………………………………………….……………………..………………. Y:………………………………………………………………….………………..……………………. Z: ………………………………………………………………….………………..…………................ (d) Namakan reagen I dan II, dan nyatakan keadaan di mana-mana yang berkenaan. [2 markah] I: …………………………………………………………………………………………..…………….. II:………………………………………………………………………………………………………… (e) Perihalkan satu kaedah untuk menguji gas W. [2 markah] ……………………………………………………………………………………………..……………..

....…………………………………………………………………………………………………………

962/5

Appendix A

Table of Cations Reactions

NaOH(aq) NH3(aq) Na2CO3(aq) K4Fe(CN)6(aq) Na2HPO4(aq)

H2S in acid medium H2S in alkaline

medium or (NH4)2S Others reagen

Al3+ White precipitate soluble in excess.

White precipitate. White precipitate. ⎯ White precipitate, soluble in mineral acid and NaOH, insoluble in CH3COOH.

⎯ White precipitate. (a) Aluminon reagent: red precipitate. (b) CH3COONa: no precipitate; white

precipitate when boiled. (c) K2CrO4: orange yellow precipitate,

dissolve in mineral asid.

Ba2+ White precipitate in concentrated solution

⎯ White precipitate. ⎯ White precipitate, soluble in HNO3 or HCl.

⎯ ⎯ (a) Dilute H2SO4 or CaSO4(aq): white precipitate.

(b) (NH4)2C2O4: white precipitate, dissolve in hot CH3COOH.

(c) K2CrO4: yellow precipitate.

Ca2+ White precipitate. ⎯ White precipitate. White precipitate in excess reagent.

⎯ ⎯ ⎯ (NH4)2C2O4: white precipitate, insoluble in CH3COOH.

Cr3+ Greyish green precipitate, soluble in excess to form green solution.

Greyish green precipitate soluble in excess to form purple solution.

Greyish green precipitate.

⎯ Green precipitate, soluble in mineral acids.

⎯ Greyish green precipitate.

(a) Excess NaOH + H2O2: yellow solution.

(b) Acidified solution + H2O2: blue solution → blue precipitate → yellow solution.

Cu2+ Blue precipitate, turns black when heated.

Blue precipitate, soluble in excess to produce dark blue solution. Soluble in NH4Cl.

Blue precipitate, turns black when heated.

Redish brown precipitate soluble in excess NH3(aq) to produce blue solution.

Blue precipitate. Black precipitate, soluble in hot HNO3.

Black precipitate. (a) SCN−: black precipitate. (b) KI: white precipitate in brown

solution.

Fe2+

Dirty green precipitate.

Dirty green precipitate, soluble in NH4Cl.

Dirty green precipitate.

Blue precipitate. ⎯ ⎯ Black precipitate. (a) K3Fe(CN)6(aq): dark blue precipitate. (b) KMnO4/H+: decolourisation at room

temperature.

Fe3+ Brown precipitate. Brown precipitate. Brown precipitate. Dark blue precipitate.

Yellowish white precipitate, soluble in mineral acids, insoluble in CH3COOH.

Yellow precipitate. Black precipitate. (a) SCN−: blood red solution. (b) K3Fe(CN)6: brown solutin. (c) KI: brown solution/yellow/black

precipitate. (d) K2CrO4: orange brown precipitate. (e) CH3COONa: red solution, brown

precipitate when heated.

Cation

Reagent

116

Lampiran A

Jadual bagi Tindak Balas Kation

NaOH(ak) NH3(ak) Na2CO3(ak) K4Fe(CN)6(ak) Na2HPO4(ak)

H2S dalam medium berasid

H2S dalam medium beralkali atau

(NH4)2S Reagen lain

Al3+ Mendakan putih, larut dalam berlebihan.

Mendakan putih. Mendakan putih. ⎯ Mendakan putih, larut dalam asid mineral dan NaOH, tak larut dalam CH3COOH.

⎯ Mendakan putih. (a) Reagen Aluminon: mendakan merah. (b) CH3COONa: tiada mendakan; mendakan putih apabila dididihkan. (c) K2CrO4: mendakan kuning jingga, larut dalam asid mineral.

Ba2+ Mendakan putih dalam larutan pekat.

⎯ Mendakan putih. ⎯ Mendakan putih, larut dalam HNO3 atau HCl.

⎯ ⎯ (a) H2SO4 cair atau CaSO4(ak): mendakan putih. (b) (NH4)2C2O4: mendakan putih, larut dalam CH3COOH panas. (c) K2CrO4: mendakan kuning.

Ca2+ Mendakan putih. ⎯ Mendakan putih. Mendakan putih dalam berlebihan.

⎯ ⎯ ⎯ (NH4)2C2O4: mendakan putih, tak larut dalam CH3COOH.

Cr3+ Mendakan hijau kelabu, larut dalam berlebihan membentuk larutan hijau.

Mendakan hijau kelabu, larut dalam berlebihan membentuk larutan ungu.

Mendakan hijau kelabu.

⎯ Mendakan hijau, larut dalam asid mineral.

⎯ Mendakan hijau kelabu.

(a) NaOH berlebihan + H2O2: larutan kuning. (b) Asidkan larutan + H2O2: larutan biru→mendakan biru→larutan kuning.

Cu2+ Mendakan biru, menjadi hitam apabila dipanaskan.

Mendakan biru, larut dalam berlebihan membentuk larutan biru tua. Larut dalam NH4Cl.

Mendakan biru, menjadi hitam apabila dipanaskan.

Mendakan coklat kemerahan, larut dalam NH3 (ak) berlebihan membentuk larutan biru.

Mendakan biru. Mendakan hitam, larut dalam HNO3 panas.

Mendakan hitam. (a) SCN-: mendakan hitam. (b) KI: mendakan putih dalam larutan coklat.

Fe2+

Mendakan hijau kotor.

Mendakan hijau kotor, larut dalam NH4Cl.

Mendakan hijau kotor.

Mendakan biru. ⎯ ⎯ Mendakan hitam. (a) K3Fe(CN)6: mendakan biru tua. (b) KMnO4/H+: penyahwarnaan pada suhu bilik.

Fe3+ Mendakan coklat. Mendakan coklat. Mendakan coklat. Mendakan biru tua. Mendakan putih kekuningan, larut dalam asid mineral, tak larut dalam CH3COOH.

Mendakan kuning. Mendakan hitam. (a) SCN-: larutan merah darah.

(b) K3Fe(CN)6: larutan coklat. (c) KI: larutan coklat/ kuning/ mendakan hitam. (d) K2CrO4: mendakan coklat jingga. (e) CH3COONa: larutan merah, mendakan coklat apabila dididihkan.

Kation

Reagen

117

NaOH(aq) NH3(aq) Na2CO3(aq) K4Fe(CN)6(aq) Na2HPO4(aq) H2S in acid medium H2S in alkaline medium or (NH4)2S Others reagent

Mg2+ White precipitate, soluble in NH4Cl.

White precipitate, soluble in NH4Cl.

White precipitate, soluble in NH4Cl.

⎯ White precipitate, soluble in mineral acid.

⎯ ⎯ (a) Magneson reagent + NaOH: blue precipitate.

(b) Na3PO4: white precipitate.

Mn2+ White precipitate, turns brown.

White precipitate, turns brown, soluble in NH4Cl.

Yellowish brown precipitate.

⎯ Yellowish brown precipitate turns brown when heated.

⎯ Yellowish brown precipitate.

(a) Sodium bismutate + HNO3: violet solution.

(b) PbO2 + HNO3 (conc): violet solution.

(c) K2S2O8 + AgNO3: violet solution. (d) NaClO + NaO: dark brown

precipirate.

Ni2+ Green precipitate.

Green precipitate, soluble in excess forms blue solution. Soluble in NH4Cl.

Green precipitate. Green precipitate. Green precipitate. ⎯ Black precipitate. (a) Dimetilglioksima reagent + NH3: red precipitate. (b) NaClO + NaOH: black precipitate.

Pb2+ White precipitate, soluble in excess.

White precipitate. White precipitate. White precipitate. White precipitate. Black precipitate. Black precipitate. (a) Dilute HCl: white precipitate, soluble when heated; reforms when cool.

(b) Dilute H2SO4: White precipitate, soluble in (NH4)2C2O4.

(c) KI: yellow precipitate, soluble when is heated, reforms when cool.

(d) K2CrO4: yellow precipitate. (e) NaClO: dark brown precipitate.

Zn2+ White precipitate, soluble in excess.

White precipitate, soluble in excess, soluble in NH4Cl.

White precipitate. White precipitate, soluble in alkali, insoluble in mineral acid.

White precipitate, soluble in NaOH, mineral acid or NH4Cl.

⎯ White precipitate. K3Fe(CN)6: orange brown precipitate.

NH4+ Pungent gas

liberated when heated.

⎯ Pungent gas liberated when heated.

⎯ ⎯ ⎯ ⎯ (a) Nessler reagent: brown precipitate. (b) Heated with NaOH, gases evolved

tested with concentrated HCl: white fume.

Cation

Reagent

118

NaOH(ak) NH3(ak) Na2CO3(ak) K4Fe(CN)6(ak) Na2HPO4(ak) H2S dalam medium

berasid

H2S dalam medium beralkali atau

(NH4)2S Reagen lain

Mg2+ Mendakan putih, larut dalam NH4Cl.

Mendakan putih, larut dalam NH4Cl.

Mendakan putih, larut dalam NH4Cl.

⎯ Mendakan putih, larut dalam asid mineral.

⎯ ⎯ (a) Reagen Magneson + NaOH: mendakan biru. (b) Na3PO4: mendakan putih.

Mn2+ Mendakan putih bertukar menjadi coklat.

Mendakan putih bertukar menjadi coklat. Larut dalam NH4Cl.

Mendakan coklat kekuningan.

⎯ Mendakan coklat kekuningan menjadi coklat apabila dipanaskan.

⎯ Mendakan coklat kekuningan.

(a) Natrium bismutat + HNO3: larutan ungu/lembayung. (b) PbO2 + HNO3 pekat: larutan ungu/ lembayung. (c) K2S2O8 + AgNO3: larutan ungu/ lembayung. (d) NaClO: mendakan coklat tua.

Ni2+ Mendakan hijau. Mendakan hijau, larut dalam berlebihan membentuk larutan biru muda. Larut dalam NH4Cl.

Mendakan hijau. Mendakan hijau. Mendakan hijau. ⎯ Mendakan hitam. (a) Reagen dimetilglioksima + NH3: mendakan merah. (b) NaClO + NaOH: mendakan hitam.

Pb2+ Mendakan putih, larut dalam berlebihan.

Mendakan putih. Mendakan putih. Mendakan putih. Mendakan putih. Mendakan hitam. Mendakan hitam. (a) HCl cair: mendakan putih, larut apabila panas; terbentuk semula apabila disejukkan. (b) H2SO4 cair: mendakan putih, larut dalam (NH4)2C2O4. (c) KI: mendakan kuning, larut apabila panas; terbentuk semula apabila disejukkan. (d) K2CrO4: mendakan kuning. (e) NaClO: mendakan coklat tua.

Zn2+ Mendakan putih, larut dalam berlebihan.

Mendakan putih, larut dalam berlebihan. Larut dalam NH4Cl.

Mendakan putih. Mendakan putih, larut dalam alkali, tak larut dalam asid mineral.

Mendakan putih, larut dalam NaOH, NH4Cl, atau asid mineral

⎯ Mendakan putih. K3Fe(CN)6: mendakan coklat jingga.

NH4+ Gas berbau hancing

dibebaskan apabila dipanaskan.

⎯ Gas berbau hancing dibebaskan apabila dipanaskan.

⎯ ⎯ ⎯ ⎯ (a) Reagen Nessler: mendakan coklat. (b) Panaskan dengan NaOH, uji gas dengan HCl pekat: wasap putih.

Kation

Reagen

119

Appendix B

Table of Anion Reactions

Dilute HCl or

H2SO4 Concentrated H2SO4 BaCl2(aq) or Ba(NO3)2(aq) AgNO3(aq)

Pb(NO3)2(aq) atau Pb(CH3COO)2(aq) FeCl3(aq) Others reagent

HCOO− Choking gas is liberated.

Gas burned with a blue flame is liberated.

⎯ White precipitate turns black.

⎯ Dark red solution; brown precipitate when heated.

(a) KMnO4/H+: decolouration. (b) CH3CH2OH + a little concentrated H2SO4:

fragrant smell

CH COO3−

Gas smell of vinegar is released when heated.

Gas of vinegar smell is released.

⎯ White precipitate in concentrated solution, soluble in HNO3 or NH3(aq).

⎯ Red solution; brown precipitate when heated.

(a) CH3CH2OH + a little concentrated H2SO4: fragrant smell.

(b) Sodalime: gas burned with blue flame without soot.

C H COO6 5−

White precipitate, soluble in hot water, white crystal formed upon cooling.

White precipitate, soluble in hot water; white crystal formed upon cooling.

⎯ White precipitate, soluble in hot water or NH3(aq).

White precipitate. Yellowish-brown precipitate.

(a) CH3CH2OH + a little concentrated H2SO4: fragrant smell.

(b) Sodalime: gas burned with yellow flame without soot.

C O2 42− ⎯ Gas burned with blue

flame and gas turned lime water chalky when heated.

White precipitate, soluble in HCl, HNO3 or H2SO4.

White precipitate, soluble in HNO3 or NH3(aq).

White precipitate, soluble in HNO3.

⎯ (a) KMnO4/H+: decolourised when heated. (b) CaCl2(aq): when precipitate.

Cl− ⎯ White fume is formed. ⎯ White precipitate, insoluble in HNO3 but soluble in NH3(aq).

White precipitate, soluble in hot water; or concentrated HCl; white crystal formed upon cooling.

⎯ MnO2(s) + H2SO4 (conc): greenish-yellow gas is liberated.

Br− ⎯ Redish-brown gas is liberated.

⎯ Light yellow precipitate, insoluble in dulute HNO3 or NH3(aq).

White precipitate, soluble in hot water, white crystal formed upon cooling.

⎯ (a) MnO2(s) + H2SO4 (conc): redish-brown gas is liberated.

(b) Cl2 /NaOCl(aq) + CCl4: redish-brown colouration at the bottom layer.

(c) Concentrated HNO3 and heated: redish-brown gas is liberated.

I− ⎯ Brown fume is formed; purple fume formed when heated.

⎯ Yellow precipitate, insoluble in dilute HNO3 or NH3(aq).

Yellow precipitate, soluble in hot water; yellow crystal formed upon cooling.

Redish brown solution. (a) Cl2 water/NaOCl(aq)/Br2 water + CCl4: redish violet colouration formed at the bottom layer.

(b) NaNO2(aq) + dilute asid: brown solution and brown gas is liberated.

Anion

Reagent

120

Lampiran B

Jadual bagi Tindak Balas Anion

HCl cair atau H2SO4 cair H2SO4 pekat

BaCl2(ak) atau Ba(NO3)2(ak) AgNO3(ak)

Pb(NO3)2(ak) atau Pb(CH3COO)2(ak) FeCl3(ak) Reagen lain

HCOO− Gas berbau sengit dibebaskan.

Gas terbakar dengan nyalaan biru dibebaskan.

⎯ Mendakan putih menjadi hitam.

⎯ Larutan merah tua; mendakan coklat apabila dipanaskan.

(a) KMnO4/H+: penyahwarnaan. (b) CH3CH2OH + sedikit H2SO4 pekat: bau buah-buahan/wangi.

CH COO3−

Gas berbau cuka dibebaskan apabila dipanaskan.

Gas berbau cuka dibebaskan.

⎯ Mendakan putih dalam larutan pekat, larut dalam HNO3 atau NH3(ak).

⎯ Larutan merah; mendakan coklat apabila dididihkan.

(a) CH3CH2OH + sedikit H2SO4 pekat: bau buah-buahan/wangi. (b) Kapur soda: gas terbakar dengan nyalaan biru tanpa jelaga.

C H COO6 5−

Mendakan putih, larut dalam air panas; hablur putih apabila disejukkan.


⎯ Mendakan putih, larut dalam air panas atau NH3(ak).

Mendakan putih. Mendakan coklat kekuningan.

(a) CH3CH2OH + sedikit H2SO4 pekat: bau buah-buahan/wangi. (b) Kapur soda: gas terbakar dengan nyalaan kuning berjelaga.

C O2 42− ⎯ Gas terbakar dengan

nyalaan biru dan gas mengeruhkan air kapur apabila dipanaskan.

Mendakan putih, larut dalam HCl, HNO3 , atau H2SO4.

Mendakan putih, larut dalam HNO3 atau NH3(ak).

Mendakan putih, larut dalam HNO3.

⎯ (a) KMnO4/H+: dinyahwarnakan apabila dipanaskan. (b) CaCl2(ak): mendakan putih.

Cl− ⎯ Wasap putih dibebaskan. ⎯ Mendakan putih, tidak larut dalam HNO3 tetapi larut dalam NH3(ak).

Mendakan putih, larut dalam air panas atau HCl pekat; hablur putih apabila disejukkan.

⎯ MnO2(p) + H2SO4 pekat: gas kuning kehijauan dibebaskan.

Br− ⎯ Gas coklat kemerahan dibebaskan.

⎯ Mendakan kuning pucat, tidak larut dalam HNO3 cair atau NH3(ak).


⎯ (a) MnO2(p) + H2SO4 pekat: gas coklat kemerahan dibebaskan. (b) Air Cl2 /NaOCl(ak) + CCl4: lapisan bawah berwarna coklat kemerahan. (c) HNO3 pekat dan panas: gas coklat kemerahan dibebaskan.

I− ⎯ Wasap coklat dibebaskan; wasap ungu dibebaskan apabila dipanaskan.

⎯ Mendakan kuning, tidak larut dalam HNO3 cair atau NH3(ak).

Mendakan kuning, larut dalam air panas; hablur kuning apabila disejukkan.

Larutan coklat kemerahan.

(a) Air Cl2/NaOCl/air Br2 + CCl4: lapisan bawah berwarna ungu. (b) NaNO2(ak) + asid cair: larutan coklat dan gas coklat dibebaskan.

Anion

Reagen

121

Dilute HCl or H2SO4 Concentrated H2SO4

BaCl2(aq) or Ba(NO3)2(aq) AgNO3(aq)

Pb(NO3)2(aq) or Pb(CH3COO)2(aq) FeCl3(aq) Others reagent

CO32 − Gas liberated can turn

lime water chalky. Gas liberated can turn lime water chalky.

White precipitate, soluble in HCl or dilute HNO3.

White precipitate turned yellow in excess; become brown when heated.

White precipitate, soluble in dilute HNO3.

Brown precipitate; gas liberated which turn lime water chalky.

MgSO4(aq)/MgCl2(aq): white precipitate.

SO32 − Brimstone smell gas/

burnt sulphur, gas decolourise KMnO4/H+.

Brimstone smell gas/ burnt sulphur, gas decolourise KMnO4/H+.

White precipitate, soluble in HCl or HNO3.

White precipitate, soluble in HNO3, NH3(aq), or SO3

2− in excess; turn black precipitate when heated.

White precipitate, soluble in dilute HNO3.

Red solution; brown precipitate when heated.

(a) I2: decolourisation. (b) KMnO4/H+: decolourisation. (c) K2Cr2O7/H+: green solution.

S O2 32 − Yellow precipitate;

brimstone smell gas/ burnt sulphur, gas decolourise KMnO4/H+.

Yellow precipitate; brimstone smell gas/ burnt sulphur, gas decolourise KMnO4/H+.

White precipitate in concentrated solution.

White precipitate turn to yellow and then brown and finally black; white precipitate soluble in excess S2O3

2−.

White precipitate, soluble in excess S2O3

2−; turn black precipitate when heated.

Purplish solution decolourise.

(a) I2: decolourisation. (b) KMnO4/H+: decolourisation. (c) K2Cr2O7/H+: green solution. (d) Ammonium molybdate + H2SO4: blue ring.

S2 − A foul (rotten egg), smell was liberated, blackening Pb(CH3COO)2 paper.

A foul (rotten egg) smell was liberated, blackening Pb(CH3COO)2 paper, yellow precipitate.

⎯ Black precipitate, soluble in hot HNO3.

Black precipitate. A yellow sediment in an acidic medium. A black sediment in an alkaline medium.

(a) KMnO4/H+: decolourisation, yellow precipitate. (b) K2Cr2O7/H+: green solution, yellow precipitate.

SO42 − ⎯ ⎯ White

precipitate, insoluble in HCl or HNO3.

⎯ White precipitate, soluble in aqueous ammonium ethanoate.

⎯ ⎯

NO2− Brown fume liberated. Brown fume liberated. ⎯ White precipitate in

concentrated solution, soluble in HNO3 or NH3.

⎯ Redish brown precipitated/solution when heated.

(a) KMnO4/H+: decolourisation. (b) K2Cr2O7/H+: green solution. (c) FeSO4 + H2SO4: brown ring. (d) Devarda alloy: pungent gas. (e) KI + dilute acid: brown sol.

NO3− ⎯ Brown fume liberated. ⎯ ⎯ ⎯ ⎯ (a) FeSO4 + H2SO4: brown ring.

(b) Devarda alloy: pungent gas. (c) Concentrated H2SO4 pekat + Cu: brown

fume, blue solution.

MnO4− ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ (a) C2O4

2-/SO32-/S2O3

2-/NO2- with H+:

decolourisation. (b) S2-: decolourisation, yellow precipitate.

Anion

Reagent

122

HCl cair atau H2SO4 cair H2SO4 pekat

BaCl2(ak) atau Ba(NO3)2(ak) AgNO3(ak)

Pb(NO3)2(ak) atau Pb(CH3COO)2(ak) FeCl3(ak) Reagen lain

CO32 − Gas yang mengeruhkan

air kapur dibebaskan. Gas yang mengeruhkan air kapur dibebaskan.

Mendakan putih, larut dalam HCl atau HNO3 cair.

Mendakan putih menjadi kuning dalam berlebihan; menjadi coklat apabila dididihkan.

Mendakan putih, larut dalam HNO3 cair.

Mendakan coklat; gas yang mengeruhkan air kapur dibebaskan.

MgSO4(ak)/MgCl2(ak): mendakan putih.

SO32 − Gas berbau belerang/

sulfur terbakar, gas menyahwarnakan KMnO4/H+.

Gas berbau belerang/ sulfur terbakar, gas menyahwarnakan KMnO4/H+.

Mendakan putih, larut dalam HCl atau HNO3.

Mendakan putih, larut dalam HNO3, NH3, atau SO3

2- berlebihan; mendakan hitam apabila dididihkan.

Mendakan putih, larut dalam HNO3.

Larutan merah; mendakan coklat apabila dididihkan.

(a) I2: penyahwarnaan. (b) KMnO4/H+: penyahwarnaan. (c) K2Cr2O7/H+: larutan hijau.

S O2 32 − Mendakan kuning; gas

berbau belerang/sulfur terbakar, gas menyahwarnakan KMnO4/H+.

Mendakan kuning; gas berbau belerang/ sulfur terbakar, gas menyahwarnakan KMnO4/H+.

Mendakan putih dalam larutan pekat.

Mendakan putih kepada kuning kepada coklat kepada hitam; mendakan putih larut dalam S2O3

2- berlebihan.

Mendakan putih, larut dalam S2O3

2- berlebihan; mendakan hitam apabila dididihkan.

Larutan ungu luntur apabila dibiarkan.

(a) I2: penyahwarnaan. (b) KMnO4/H+: penyahwarnaan. (c) K2Cr2O7/H+: larutan hijau. (d) Ammonium molibdat + H2SO4 pekat: cincin biru.

S2 − Gas berbau telur busuk dibebaskan, gas menghitamkan kertas Pb(CH3COO)2.

Gas berbau telur busuk dibebaskan, gas menghitamkan kertas Pb(CH3COO)2, mendakan kuning.

⎯ Mendakan hitam, larut dalam HNO3 panas.

Mendakan hitam. Mendakan kuning dalam medium berasid. Mendakan hitam dalam medium beralkali.

(a) KMnO4/H+: penyahwarnaan, mendakan kuning. (b) K2Cr2O7/H+: larutan hijau, mendakan kuning.

SO42 − ⎯ ⎯ Mendakan putih,

tidak larut dalam HCl atau HNO3.

⎯ Mendakan putih, larut dalam ammonium etanoat akueus.

⎯ ⎯

NO2− Wasap coklat

dibebaskan. Wasap coklat dibebaskan.

⎯ Mendakan putih dalam larutan pekat, larut dalam HNO3 atau NH3.

⎯ Mendakan/larutan coklat kemerahan apabila dipanaskan.

(a) KMnO4/H+: penyahwarnaan. (b) K2Cr2O7/H+: larutan hijau. (c) FeSO4 + H2SO4 cair: cincin coklat. (d) Aloi Devarda: gas berbau hancing. (e) KI + asid cair: larutan coklat.

NO3− ⎯ Wasap coklat

dibebaskan. ⎯ ⎯ ⎯ ⎯ (a) FeSO4 + H2SO4 pekat: cincin coklat.

(b) Aloi Devarda: gas berbau hancing. (c) H2SO4 pekat + Cu: wasap coklat; larutan biru.

MnO4− ⎯ ⎯ ⎯ ⎯ ⎯ ⎯ (a) C2O4

2-/SO32-/S2O3

2-/NO2- dengan H+:

penyahwarnaan. (b) S2-: penyahwarnaan, mendakan kuning.

Anion

Reagen

123

O

962 sp chemistry

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