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Chemistry Perfect Score Module 2012 1 BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH DAN SEKOLAH KECEMERLANGAN MODUL PERFECT SCORE & X A-PLUS SEKOLAH BERASRAMA PENUH TAHUN 2012 PANEL PENYEDIA DAN PEMURNI: Pn. Wan Noor Afifah Binti Wan Yusoff (Ketua) SBPI GOMBAK Tn Hj Ja'afar B Bajuri SMS SULTAN MAHMUD Pn. Norini Binti Jaafar SEKOLAH SULTAN ALAM SHAH Tn Hj Che Malik Bin Mamat SBPI BATU RAKIT Pn. Rossita Binti Radzak SMS TUANKU MUNAWIR En Jong Kak Ying SMS KUCHING En Ooi Yoong Seang SMS MUAR Che Ramli B Che Ismail SMS FARIS PETRA Pn Masodiah Bt Mahfodz SMS HULU SELANGOR Pn. Noraini Binti Zakaria SMS SULTAN MOHAMAD JIWA

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  • Chemistry Perfect Score Module 2012 1

    BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH

    DAN SEKOLAH KECEMERLANGAN

    MODUL PERFECT SCORE &

    X A-PLUS

    SEKOLAH BERASRAMA PENUH TAHUN 2012

    PANEL PENYEDIA DAN PEMURNI:

    Pn. Wan Noor Afifah Binti Wan Yusoff (Ketua) SBPI GOMBAK

    Tn Hj Ja'afar B Bajuri SMS SULTAN MAHMUD

    Pn. Norini Binti Jaafar SEKOLAH SULTAN ALAM SHAH

    Tn Hj Che Malik Bin Mamat SBPI BATU RAKIT

    Pn. Rossita Binti Radzak SMS TUANKU MUNAWIR

    En Jong Kak Ying SMS KUCHING

    En Ooi Yoong Seang SMS MUAR

    Che Ramli B Che Ismail SMS FARIS PETRA

    Pn Masodiah Bt Mahfodz SMS HULU SELANGOR

    Pn. Noraini Binti Zakaria SMS SULTAN MOHAMAD JIWA

  • Chemistry Perfect Score Module 2012 2

    CHEMISTRY PERFECT SCORE MODULE 2012

    CONTENT

    1 Guidelines &

    Anwering Techniques

    Format of an instrument of chemistry Construct requirement Guidelines for answering paper 1 Guidelines for answering paper 2 Guidelines for answering paper 3 The common command words in paper 2

    2 Set 1

    The structure of Atom Chemical Formulae and equations Periodic Table of Elements Chemical Bonds

    3 Set 2 Electrochemistry Oxidation and Reduction

    4 Set 3

    Acids and Bases Salts Rate of reaction Thermochemistry

    5 Set 4 Carbon compounds Manufactured Substance in Industry Chemicals for Consumers

    6 Set 5 Paper 3 set 1 Paper 3 set 2 Paper 3 set 3

  • Chemistry Perfect Score Module 2012 3

    CHEMISTRY

    PERFECT SCORE MODULE

    GUIDELINES

    & ANSWERING TECHNIQUES

    CHEMISTRY SPM

  • Chemistry Perfect Score Module 2012 4

    GUIDELINES AND ANSWERING TECHNIQUES FOR SPM CHEMISTRY PAPER

    1.0 FORMAT OF AN INSTRUMENT OF CHEMISTRY BEGINNING SPM 2003

    No Item Paper 1

    (4541/1)

    Paper 2

    (4541/2)

    Paper 3

    (4541/3)

    1 Type of instrument Objective test Subjective test Written Practical Test

    2

    Type of item Objective it Section A :

    Structured Item

    Section B :

    Essay restricted response Item

    Section C :

    Essay extended response Item

    Subjective Item :

    Structured Item

    Extended Response Item:

    (Planning an experiment)

    3

    Number of

    question

    50 (answers all) Section A : 6 (answer all)

    Section B : 2 (choose one)

    Section C : 2 (choose one)

    Structured Item :

    1/2 items (answer all)

    Extended Response Item :

    1 item

    5 Duration of time 1 hour 15

    minutes

    2 hour 30 minutes 1 hour 30 minutes

    2.0 CONSTRUCT REQUIREMENT

    Construct Paper 1 Paper 2 Paper 3

    Knowledge 20 m ( No 1- 20) 14 -

    Understanding 15 m ( No 21 35) 21 -

    Application 15 m ( No 36 50) 29 -

    Analysis - 21 -

    Synthesizing - 15 -

    Science process - - 50

    Total mark 50 100 50

    3.0 TIPS TO SCORE A CHEMISTRY

    3.1 Master the topics that contains the basic concepts of chemistry :

    1. The structure of the atom 2. Chemical Formulae And Equations 3. Periodic Table 4. Chemical Bond

    3.2 Familiarize with different types of questions as listed below and complete the previous SPM

    papers:

    1. Objectives questions (MCQ) (Paper 1) 2. Structured questions ( Paper 2 & 3) 3. Essays (Paper 2) 4. Planning an experiment ( Paper 3) 5. Draw and label the diagram 6. Writing chemical equation( balanced equation, ionic equation, half equation)

    3.3 Try to get :-

    40 marks above for paper 1 60 marks above for paper 2 40 marks above for paper 3 (Total = 180/2 =80 , A+ in SPM)

  • Chemistry Perfect Score Module 2012 5

    4.0 GUIDELINE FOR ANSWERING PAPER 1

    4.1 Paper 1 questions test students on

    1. Knowledge ( Number 1 20) 2. Understanding ( Number 21 35) 3. Application ( Number 36 50 )

    4.2 Score in paper 1 Indicates students level of understanding in chemistry: Less than 20 very weak 20 25 - weak 26 30 - average 31 39 - good 40 45 - very good 46 50 - excellent.

    4.3 Answer all SPM objective questions (2003 2010). Objective questions for each year contain all topics. If your score in paper 1 is 40 and above, you will able to answer questions in paper 2 & 3

    easily.

    5.0 GUIDELINE FOR ANSWERING PAPER 2 (STRUCTURE AND ESSAY)

    5.1 Paper 2 questions test student on

    1. Knowledge 2. understanding 3. analyzing 4. synthesizing

    5.2 Steps taken are:

    1. Underline the command word and marks allocated for each question. 2. Match the command word to the mark allocated for each question. 1 point is awarded 1

    mark.

    3. Follow the needs of the question (Refer to the command words, page .) 4. Unnecessary repetition of the statement in the question is not required.

    5.3 Three types of questions which involve experiments in paper 2:

    I. Type 1 Describe an experiment onInclude a labeled diagram in your answer 1. Diagram

    2. Procedure

    3. Observation/example/data/calculation/equation/sketch of graph/conclusion

    II. Type 2 Describe an experiment( The diagram will support your answer.) 1. No mark is allocated for a diagram 2. Procedures 3. Observation/example/calculation/equation/sketch of graph/conclusion

    III. Type 3 Describe a chemical/confirmatory test for . 1. Procedure 2. Observation 3. Conclusion

    6.0 GUIDELINE FOR ANSWERING PAPER 3

    6.1 Structure Question 1/2 test the mastery of 11 Scientific Skills

    1. Observing

    2. Classifying

    3. Inferring

    4. Measuring (burette , stopwatch, thermometer, voltmeter)

    5. Predicting

    6. Communicating( e.g construct table and draw graph)

    7. Space-Time Relationship

    8. Interpreting Data

  • Chemistry Perfect Score Module 2012 6

    9. Defining Operationally

    10. Controlling Variables

    11. Hypothesizing

    Each answer is allocated mark as follows: 3 marks/2 marks/1 mark/0 Score : 11 X 3 = 33

    Example of operational definition:

    1. what you do

    2. what you observe correctly

    Example:

    1. When acid is added into latex, white solid is formed.

    When acid is added into latex, latex coagulated.- wrong

    2. When the higher the concentration sodium thiosulphate solution is added into sulphuric acid, time taken for

    `X~ mark to disappear from sight is shorter.

    3. When iron nail is coiled with copper and immersed into jelly mixed with potassium hexacyanoferrate(III) and

    phenolphthalein solution, blue spot/colouration is formed.

    Operational definition for What you do What is observed

    1. Rusting of iron When an iron nail coiled with a less electropositive metal is immersed in hot

    agar-agar added with potassium

    hexacyanoferrate (III) solution,

    Blue spots are formed

    2. Coagulation of latex When acid is added to latex White solid is formed

    3. Reactivity of Group 1 elements

    When a metal which is lower in Group 1 is

    put in a basin half filled with water

    Brighter flame is formed

    4. Precipitation of silver chloride

    When silver nitrate solution is added to

    sodium chloride solution

    White solid is formed

    5. Voltaic cell When two different metals are dipped into an electrolyte

    The needle of the voltmeter

    deflects

    6. An acid When a blue litmus paper is dipped into a substance which is dissolved in water,

    Blue litmus paper turns red

    Hypothesis: Relate manipulated variable followed by responding variable with direction.

    Example:

    1. The higher temperature of the reactant the higher the rate of reaction 3 marks The temperature of the reactant affect the rate of reaction 2 marks 2. Hexene decolourised brown bromine water but hexane does not decolourised brown bromine water.

    3. When acid is added into latex, latex coagulates, when ammonia is added into latex, latex cannot coagulates

    4. Question 3 (essay) Test The Mastery of Planning Experiment .

    Planning should include the following aspects:

    1. Aim of the experiment/Statement of the problem

    2. All the variables

    3. Statement of the hypothesis

    4. List of substances/material and apparatus should be separated

    5. Procedure of the experiment

    6. Tabulation of data Score : (5 X 3) + 2 = 17

    The question normally starts with certain situation related to daily life.

    Problem statement/ aim of the experiment / hypothesis and variable can be concluded from the situation given.

    State all the variables

    Manipulated variable :

    Responding variable :

    Constant variable: list down all the fixed variables to ensure the outcome of the responding variable is

    related only to the manipulated variables.

  • Chemistry Perfect Score Module 2012 7

    Separate the substances and apparatus

    - Separate the substances and apparatus - Apparatus : list down the apparatus for the experiment.

    Example: Rate of reaction stop watch Termochemistry - thermometer

    Procedure :

    All the steps taken in the procedure must include the apparatus used, quantity and type of substance (powder,

    solution, lumps etc). No mark is allocated for the diagram. The complete labeled diagram can help students in :

    I. Writing the steps taken in the procedure II. Listing the apparatus and materials

    Tabulation of data:

    The number of columns and rows in the table is related to the manipulated and responding variables

    Units must be written for all the titles in each row and column of the table

    DO NOT WRITE the observation/inference/conclusion in the table.

    7.0 THE COMMON COMMAND WORDS IN PAPER 2 & PAPER 3 CHEMISTRY

    The question normally starts with a command word.

    Students must know the meaning of the command word to make sure that the answer given is according to the questions requirement.

    Match the command word to the mark allocated for each question.

    Command word Explanation/example

    Name/State the

    name

    (paper 2 & 3)

    Give the name , not the formula.

    Example: Name the main element added to copper to form bronze.

    Wrong answer : Sn.

    Correct answer : Tin

    State

    (paper 2 & 3)

    Give brief answer only. Explanation is not required.

    Example : State one substance which can conduct electricity in solid state.

    Answer : Copper

    State the

    observation

    (Paper 2 & 3)

    Write what is observed physically.

    Example 1 : State one observation when magnesium powder is added to hydrochloric

    acid. [ 1 mark]

    Wrong answer : Hydrogen gas is released.

    Correct answer : Gas bubbles are released

    Indicate the change of colour , give the initial and final colour of the substance/chemical.

    Example 2: What is the colour change of copper(II) suphate solution. [2 marks]

    Wrong answer: The solution becomes colourless

    Correct answer : The blue colour of the solution becomes colourless

    Explain

    (Paper 2 & 3)

    Give the answer with reasons to explain certain statement / fact / observation/ principal.

    Example 1 : Explain why bronze is harder than pure copper [4 marks]

    Correct answer :

    - Copper atoms in pure copper are all of the same size and ...........1 - they are arranged in layers that can slide easily when force is applied ...........1 - The presence of tin atoms in bronze that are different in size disturb the

    orderly arrangement of atoms in bronze. ...........1

    - This reduces the layer of atoms from sliding. ...........1

    What is meant by..

    (Definition)

    (Paper 2 & 3)

    Give the exact meaning

    Example: What is meant by hydrocarbon.

    Wrong answer: A compound that contains carbon and hydrogen

    Correct answer: A compound that contains carbon hydrogen only

    Describe chemical

    test

    (Paper 2 & 3)

    State the method to conduct the test , observation and conclusion.

    Example : Describe how to identify the ion present in the solution . [3 marks]

    Answer : - Pour in 2 cm3 of the solution in a test tube. Add a few drops of sodium

    hydroxide solution and the test tube is shake the test tube ...........1

  • Chemistry Perfect Score Module 2012 8

    - A reddish brown precipitate formed. ...........1

    - Fe3+

    ions present 1

    Describe gas test.

    (Paper 2 & 3)

    State the method to conduct the test observation and conclusion.

    Example: Describe the confirmatory test for gas released at the anode (oxygen). [3 marks]

    Wrong answer: Test with a glowing wooden splinter.

    Correct answer: - Place a glowing wooden splinter to the mouth of the test tube ...1 - The glowing wooden splinter is lighted up ...1 - Oxygen gas is released ...1

    Describe an

    experiment

    ( 8 - 10 marks)

    (Paper 2)

    - No mark is awarded for the diagram. The diagram can help students write the steps taken in the procedure.

    - List of materials 1m - List of apparatus 1m - Procedure ( 5 8 m) - Observation/tabulation of data/ calculation/sketch of the graph/ chemical equation /ionic

    equation /conclusion etc. - Any additional details relevant derived from the question.

    Plan an

    experiment

    ( 17 marks)

    ( Paper 3)

    Answer the question according the requirement :

    Problem statement/Aim of experiment

    Hyphotesis

    Variables

    List of substances and apparatus

    Procedure

    Tabulation of data Note: For question 3, unlike PEKA report students only need to answer according to what is

    stated in the question.

    - No mark for the diagram. Diagram can help student writing the steps taken in the

    procedure.

    Describe the

    process Describe the

    structure . Describe and write equation Describe how (Paper 2 & 3)

    Give relevant details derived from the question.

    Predict

    (Paper 2 & 3)

    Make a prediction for something that might happen based on facts

    Example: Experiment 1 is repeated using a larger beaker. Predict the increase in

    temperature

    Answer : The increase in temperature is lower than experiment 1.

    Compare

    (Paper 2)

    Give the similarities and differences between two items/ situations

    Differentiate

    (Paper 2)

    Give differences between two items/situations

    Example : State three differences between ionic and covalent compound.

    Answer : State three properties of ionic compound and three properties covalent compound

    Draw a labeled

    diagram of the

    apparatus

    (Paper 2)

    Draw a complete set up of apparatus

    (i) Functional set up of apparatus (ii) Complete label (iii) Shade solid, liquid and gas correctly. (iv) Draw an arrow and label heat if the experiment involves heating

    Draw a diagram

    to show the

    bonding formed in

    the compound

    (Paper 2)

    (i) Ionic compound The number of electrons in each shell is correct, 2 electrons in the first shell

    and 8 electrons in the second and third shell.

    Show the charge of each particle. Write the symbol of each element at the centre of the ion. (ii) Covalent compound

    The number of electrons in each shell is correct, 2 electrons in the first shell and 8 electrons in the second and third shell.

    The number of atoms sharing pair of electrons is correct.

    Can be obtained from the diagram

  • Chemistry Perfect Score Module 2012 9

    Write the symbol of each element at the center of each atom in the molecule.

    Draw graph

    (Paper 3)

    Draw graph as follows :

    Label the two axis with the correct unit

    Choose suitable scale, the size of the graph should be at least of the size of the graph paper.

    Plot all the points correctly

    Smooth graph ( curve or straight line )

    For the determination of the rate of reaction (i) Draw a tangent at the curve. (ii) Draw a triangle at the tangent Calculate the gradient of the tangent

    Draw the energy

    level diagram

    ( Paper 2)

    Draw an arrow for the vertical axis only and label with energy.

    Draw two horizontal lines for the reactants and products

    Draw the

    arrangement of

    particles in solid,

    liquid and gas.

    (Paper 2)

    Solid: Draw at least three layers of particles closely packed in orderly manner and they are not overlap.

    Liquid : The particles packed closely but not in orderly manner

    Gas : The particles are very far apart from each other

    Draw the direction

    of electron flow

    (Paper 2 /3)

    Draw the direction for the flow of electrons on the circuit, not through the solution.

    Write chemical

    equation

    (Paper 2 & 3)

    Write the balanced chemical equation

    Differentiate : (i) Balanced chemical equation (ii) Ionic equation (iii) Half equation for oxidation (iv) Half equation for reduction

    Calculate

    (Paper 2 & 3) Show all the steps taken

    Give final answer with unit.

    Classify

    (Paper 3) Draw table to represent the classification.

  • Chemistry Perfect Score/X A-Plus Module 2012 10

    CHEMISTRY MODULE

    SET

    1. The Structure of Atom 2. Chemical Formulae and Equations 3. Periodic Table of Elements 4. Chemical Bonds

  • Chemistry Perfect Score/X A-Plus Module 2012 11

    SECTION A

    1. Table 1 shows the proton number and nucleon number for atoms L, M and N.

    Atom Proton number Nucleon number

    L 16 32

    M 17 35

    N 17 37

    Table 1

    (a) (i) What is meant by proton number ?

    [1 mark ]

    (ii) What is the number of neutrons in atom M ?

    [1 mark ]

    (b) Which atoms are isotopes ? Explain your answer.

    [2 marks]

    (c) (i) Write the electron arrangement for atom L.

    [1 mark ]

    (ii) State the position of atom L in the Periodic Table

    [1 mark ]

    (iii) Explain your answer in c (ii)

    ..

    . [2 marks ]

    (d) Write the formula of ion formed from atom M

    [1 mark ]

  • Chemistry Perfect Score/X A-Plus Module 2012 12

    2 Diagram 2 shows part of the Periodic Table of Elements.T, U, V, W, X, Y and Z do not represent the

    actual symbol of the elements.

    1 18

    2 13 14 15 16 17

    V X W Z

    U Y

    T

    Diagram 2

    (a) Write the electron arrangement of U atom.

    ............................. [1 mark ]

    (b) (i) Which of the element exist as a monoatomic gas ?

    ....................................................................................................................... [1 mark ]

    (ii) Explain your answer in (b)(i).

    ..

    . .............................................................................................................. [2 marks ]

    (c) V reacts with W to form a compound.

    (i) Write the formula for the compound formed.

    [1 mark ]

    (ii) Draw the electron arrangement for the compound formed in (c)(i).

    [2 marks ]

    (d) (i) Choose an element that is a halogen.

    [1 mark ]

    (ii) Which element forms an amphoteric oxide ?

    . [1 mark]

    (iii) Choose the element which form a coloured ion or compound

    . [1 mark ]

  • Chemistry Perfect Score/X A-Plus Module 2012 13

    3 Table 3 shows the element in Period 3 with their respective proton numbers.

    Element Na Mg Al Si P S Cl Ar

    Proton number 11 12 13 14 15 16 17 18

    Table 3

    (a) (i) Write the electron arrangement of sulphur atom,

    [1 mark ]

    (ii) In which group of the Periodic Table is Sulphur, S located ?

    .....................................................................................................................................

    [1 mark ]

    (b) (i) How does the atomic size change when going across the Period from left to right ?

    ............................................................................................................................. ..............

    [1 mark ]

    (ii) Explain your answer in 2(b)(i)

    ...........................................................................................................................................

    ............................................................................................................................. ...............

    [2 marks ]

    (c) Argon, Ar is chemically unreactive. Explain why ?

    ............................................................................................................................. ................

    ............................................................................................................................................

    [2 marks ]

    (d) Which of the element when reacts with oxygen produces an amphoteric oxide ?

    ........................................................................................................................... [1 mark ]

    (e) Write the chemical equation when sodium react with water.

    ............................................................................................................................. ............

    [2 marks ]

    4. Table 4 shows the electron arrangement of atoms of elements J,K,L,M and N.

    Element Electron arrangement of atom

    J 1

    K 2.8.1

    L 2.8.6

    M 2.8.7

    N 2.8.8

    Table 4

    (a) State one element in Table 4 which is metal and non-metal?

    Metal : .......................................................................................................

    Non- metal : ........................................................................................................

    [2 marks]

  • Chemistry Perfect Score/X A-Plus Module 2012 14

    (b) (i) State an element that exist as a diatomic gas. Explain your answer.

    ...... [1 mark ]

    (ii) Explain your answer in (b)(i)

    .... [3 marks]

    (c) (i) What is the Proton Number for atom M

    ............................................................................................................................. .........

    [1 mark ]

    (ii) Which group is atom M located in the Periodic Table ? Explain your answer.

    .....................................................................................................................................

    ....................................................................................................................................

    [2 marks ]

    (d) Arrange atoms K, L and M in increasing atomic size

    .......................................................................................................................................

    [1 mark ]

    (e) Write the formula for K ion.

    ......................................................................................................................................

    [1 mark ]

    (f) K and M react to form an ionic compound.State the formula for this compound.

    .....................................................................................................................................

    [1 mark ]

    5 (a) Table 5 shows three substances and their respective chemical formulae.

    Name of substance Chemical formula

    Chlorine Cl2

    Magnesium Mg

    Magnesium chloride MgCl2

    Table 5

    Use information from Table 1 to answer the following questions :

    (i) State one substance which exists as an atom.

    ..[1 mark]

    (ii) Write the ionic formula for the substance in (a) (i).

    .. [1 mark]

    (iii) Which substance has the lowest melting point?

    .. [1 mark]

  • Chemistry Perfect Score/X A-Plus Module 2012 15

    (iv) What is the state of matter of chlorine at room temperature?

    .. [1 mark]

    (v) Magnesium chloride can conduct electricity in aqueous solution. Give a reason.

    .. [1 mark]

    (b) Graph 1 shows the temperature against time when molten of acetamide, C2H5NO is cooled.

    Graph 1

    (i) State the type of compound of acetamide.

    .......... [1mark]

    (ii) State the melting point of acetamide.

    . [1 mark]

    (iii) Describe the movement of the particles of acetamide between A and B during cooling.

    [1 mark]

    (iv) Draw the arrangement of particles of acetamide at stage CD.

    [1 mark]

    Temperature / 0C

    Time / s

    T1

    T2

    T3

    A

    B C

    D

  • Chemistry Perfect Score/X A-Plus Module 2012 16

    Heat

    6 (a) In a close container, contains 3.0 dm3 of carbon dioxide gas at room temperature.

    (i) How many molecules are there in 3.0 dm3 of carbon dioxide gas, CO2 ?

    [Avogadros number = 6.02 x 1023 mol-1] [1 mole of gas occupies 24 dm

    3 at room temperature]

    Use: Number of mole = Number of particles

    6.02 x 1023

    mol-1

    [2 marks]

    (ii) Calculate the mass of carbon dioxide gas in the container

    [Relative molecular mass for CO2 = 44]

    Use: Number of mole = mass

    molar mass

    [1 mark]

    (b) Diagram 6 shows the set-up of apparatus for an experiment to determine the empirical formula

    of magnesium oxide..

    Diagram 6

    Table 1 shows the results of this experiment

    Description Mass (g)

    Mass of crucible + lid 34.0

    Mass of crucible + lid + magnesium ribbon 36.4

    Mass of crucible + lid + magnesium oxide 38.0

    Table 1

    (b) (i) What is the meaning of emperical formula

    .

    .. [1 mark]

    Magnesium ribbon

  • Chemistry Perfect Score/X A-Plus Module 2012 17

    (ii) Base on table 1, calculate the mass of:

    Magnesium :

    Oxygen :

    [2 marks]

    (iii) Calculate the ratio of mole of magnesium atoms to oxygen atoms.

    [Relative atomic mass: O=16, Mg =24]

    [1 mark]

    (iv) Determine the empirical formula of magnesium oxide.

    [1 mark]

    (v) Why was the crucible lid opened once in a while during the experiment?

    .... [1 mark]

    (v) State why the empirical formula of copper oxide cannot be determine by using the same

    technique.

    .... [1 mark]

    7. (a) What is the meaning of molecular formula?

    ...

    .. [1 mark]

    (b) Diagram 7.1 shows an incomplete equation which is one of the steps involved in determining the empirical formula.

    Complete this equation.

    Diagram 7.1

    Mass

    Relative atomic mass =

  • Chemistry Perfect Score/X A-Plus Module 2012 18

    (c) Diagram 7.2 shows the apparatus set-up for two methods used to determine the empirical formula of two compounds.

    Method 1 Method II

    Diagram 7.2

    (i) Which method is suitable to be used to determine the empirical formula of magnesium oxide?

    . [1 mark]

    (ii) Why did you choose the method in 2(c)(i)?

    . [1 mark]

    (iii) When carrying out an experiment using Method I, why does the crucible lid need to be opened

    once a while?

    [1 mark]

    (d) Diagram 7.3 shows the results for an experiment to determine the empirical formula of lead oxide.

    Diagram 7.3

    Based on Diagram 2.3, determine the values of the following

    [Relative atomic mass of O =16 , Pb = 207]

    (i) Mass of lead

    = g [1 mark]

    (ii) Number of moles of lead.

    = mol [1 mark]

    (iii) Mass of oxygen

    = ..g [1 mark]

    (iv) Number of moles of oxygen.

    = mol [1 mark]

    (v) Empirical formula of oxide of lead.

    = [1 mark]

    Mass of combustion tube + porcelain dish = 54.00 g

    Mass of combustion tube + porcelain dish + lead oxide = 107.52 g

    Mass of combustion tube + porcelain dish + lead = 103.68 g

  • Chemistry Perfect Score/X A-Plus Module 2012 19

    8. Diagram 8 shows the apparatus set-up to determine the empirical formula of copper oxide.

    Diagram 8

    Table 8 shows the result of this experiment.

    Description Mass(g)

    Combustion tube + porcelain dish 42.25

    Combustion tube + porcelain dish + copper oxide 52.25

    Combustion tube + porcelain dish + copper 50.25

    Table 8

    (a) (i) What is the meaning of empirical formula?

    [1 mark]

    (ii) State the function of the anhydrous calcium chloride.

    .. [1 mark]

    (b) (i) Based on Table 8, determine the mass of:

    Copper:

    =..g

    Oxygen:

    = ..g [2 marks]

    (ii) Calculate the ratio of moles of copper atoms to oxygen atoms.

    [Relative atomic mass: O = 16 ; Cu = 64]

    [1 mark]

  • Chemistry Perfect Score/X A-Plus Module 2012 20

    (iii) Determine the empirical formula of copper oxide.

    [1 mark]

    (c) (i) Why is hydrogen gas passed through the combustion tube after heating has

    stopped?

    .

    . [1 mark]

    (ii) State how to determine that the reaction between copper oxide with hydrogen has

    completed.

    [1 mark]

    (d) (i) State why the empirical formula of magnesium oxide cannot be determined by using the same technique.

    [1 mark]

    (ii) State the name of another metal oxide whose empirical formula can be

    determine using the same technique.

    .. [1 mark]

    SECTION B

    9 (a) Diagram 9.1 shows the atomic structure of two carbon isotopes.

    Diagram 9.1

    (a) Compare the two isotopes above in terms of number of proton, number of electron, nucleon number,physical properties and chemical properties.

    [6 marks]

    Nucleus

    6 neutrons

    Nucleus

    8 neutrons

  • Chemistry Perfect Score/X A-Plus Module 2012 21

    (b) Diagram 9.2 shows the set up of apparatus used in experiment to determine the melting points of X.

    Diagram 9.2

    (i) Suggest one example of substance X. [1 mark]

    (ii) State the name of P. Explain why P is used? [2 marks]

    (iii) Graph 9 shows the heating curve of X.

    Graph 9

    Describe Graph 9 in terms of state of matter, particles arrangement, kinetic energy of

    particles and attraction forces between particles.

    [10 marks]

    (iv) After t3 minutes, X is cooled at room temperature. Sketch a graph of temperature against time for cooling process.

    .

    [2 marks]

    Temperature / 0C

    Suhu / 0C

    Time/

    minutes

    Masa / minit

    100

    30

    t1 t2 t3

    80

    0

    Q

    X

    Heat

    P

  • Chemistry Perfect Score/X A-Plus Module 2012 22

    10 (a) Helium, He4

    2 exists as a monoatomic gas whereas chlorine, Cl35

    17 exists as a diatomic gas.

    Explain why.

    [6 marks]

    (b) Table 10.1 shows the proton number of magnesium, chlorine and carbon.

    Element

    Magnesium Chlorine Carbon

    Proton number 12 17 6

    Table 10.1

    (i) Carbon reacts with chlorine to form a compound.

    What type of the compound formed?

    Draw the electron arrangement to show the chemical bond in the compound.

    [3 marks]

    (ii) Explain how ionic bond is formed between magnesium and chlorine atoms.

    [7 marks]

    (c) Diagram 10 shows the set-up of apparatus to investigate the electrical conductivity of

    naphthalene and sodium chloride solution.

    Diagram 10

    Table 10.2 shows the result of the experiments.

    Compound Observation

    Naphthalene Bulb does not light up

    Sodium chloride solution

    Bulb lights up

    Table 10.2

    Explain the electrical conductivity of the two compounds.

    [4 marks]

    Bulb

    Carbon

    electrode

    Compound

  • Chemistry Perfect Score/X A-Plus Module 2012 23

    Empirical formula is CH2O.

    Relative molecular mass is 60.

    Reacts with calcium carbonate to produce a type of gas that turns lime

    water chalky.

    11. (a) The following are the formulae of two compounds.

    Al2O3 PbO2

    (i) Based on the two formulae, write the formula for ion aluminium and ion lead

    [2 marks]

    (ii) Name both compounds based on the IUPAC nomenclature system.

    [2 marks]

    (b) The following information is about an organic compound, K.

    Based on the information given:

    (i) Determine the molecular formula of K.

    [Relative atomic mass : H = 1, C = 12, O = 16]

    [3 marks]

    (ii) Write a balanced chemical equation for the reaction of compound K with calcium carbonate.

    [2 marks]

    (c) Diagram 11 shows the apparatus set up for experiment of decomposition of copper(II) carbonate. In this

    experiment copper(II) oxide and carbon dioxide gas are formed.

    Based on Diagram 11

    (i) State two observations.

    [2 marks]

    (ii) Write a balanced chemical equation for the reaction

    [2 marks]

    (iii) ) State two informations from the chemical equation in (c)(ii). [2 marks]

    Diagram 11

    Copper(II) carbonate powder

    Lime water

    Heat

  • Chemistry Perfect Score/X A-Plus Module 2012 24

    (v) Calculate the mass of the copper(II) oxide formed from the decomposition of 12.4 g of copper(II) carbonate.

    [ Relative atomic mass of C = 12; O = 16; Cu = 64]

    [3 marks]

    (vi) In other experiment 4.0 g copper(II) oxide is reacted with hydrogen gas to produce copper and water. If the mass of copper in copper(II) oxide is 3.2 g, calculate the mass of oxygen and the simplest mole

    ratio for the copper atoms to oxygen atoms

    [ Relative atomic mass of O = 16; Cu = 64]

    [2 marks]

    12. Table 12 shows the positive and negative ions in three salts solution.

    Name of salt Positive ion Negative ion

    Iron(III) chloride Fe3+

    Cl-

    Potassium sulphate K+ SO4

    2-

    Lead(II) nitrate Pb2+

    NO3-

    Table 12

    Use the information in Table 12 to answer the following questions.

    (a) (i) What are another name for a positively charged ion and negatively charged ion?

    [2 marks]

    (ii) Name the ions in iron(III) chloride.

    [2 marks]

    (iii) Write the formula for potassium sulphate.

    [1 mark]

    (b) When 10 cm3 of 0.5 mol dm

    -3 potassium sulphate solution is added to excess lead(II) nitrate

    solution, a white precipitate is formed.

    (i) Name the white precipitate and write the chemical equation for the reaction.

    [3 marks]

    (ii) Describe the chemical equation in (b)(i).

    [1 mark]

    (iii) Calculate the mass of precipitate formed.

    [Relative atomic mass of O = 16; S = 32; Pb = 207]

    [4 marks]

    (c) The information below is regarding an organic compound Z.

    Relative molecular mass is 46

    Carbon : 52.2%

    Hydrogen : 13.0%

    Oxygen : 34.8%

    Relative atomic mass of H = 1; C = 12 and O = 16

    Based on the information of the organic compound Z:

    (i) Determine the molecular formula for compound Z and [6 marks]

    (ii) Draw its structural formula.

    [1 mark]

  • Chemistry Perfect Score/X A-Plus Module 2012 25

    SECTION C

    13 (a) An experiment is carried out using Group 1 elements; X, Y and Z react with oxygen

    gas.The set-up of apparatus and observations of the reaction are shown in Table 13.

    Set Set-up of apparatus Observation

    I

    Burns slowly and

    white fumes formed

    II

    Burns vigorously and

    white fumes formed

    III

    Burns rapidly and

    white fumes formed

    Table 13

    (i) Based on the observation in Table 13, compare the reactivity of element X and Y.

    Explain your answer.

    [5 marks]

    (ii) Suggest the name of element Z. Using the symbol of element suggested, write the

    chemical equation for the reaction in set III.

    [3 marks]

    (b) State how elements of Group 1 are stored in laboratory and give a reason.

    [2 marks]

    (c)

    Using an example of Group 1 element, describe an experiment to prove above statement.

    Your description should include the following :

    List of material and apparatus

    Procedures of the experiment

    Observation

    Chemical equation [10 marks]

    Group 1 elements react with water to produce alkaline solution.

    Z

    X

    Y

  • Chemistry Perfect Score/X A-Plus Module 2012 26

    14 Table 14 shows the melting point, boiling point and electrical conductivity of compound PQ2 and compound XY.

    Compound

    Melting point and Boiling point

    Electrical conductivity

    Solid Molten

    P Low No No

    Q High No Yes

    Table 14

    (a) Suggest one possible compound for P. State the type of compound for P.

    Explain why P has low melting and boiling points.

    [4 marks]

    (b) Chemical formula of compound P is XY. Suggest one possible electron arrangement of atom X and atom Y.

    State the type of chemical bond and explain how the bond is formed between atom X and

    atom Y.

    [7 marks]

    (c) Plan one laboratory experiment to investigate the electrical conductivity of compound Q. Your answer should include the following :

    A list of material and apparatus

    Procedure of the experiment

    Observation of the experiment

    A labeled diagram showing the apparatus set-up [9 marks]

    15 (a) Metal P has the following characteristics:-

    Based on the information above, state the method used to determine the empirical formula of oxide of

    metal P.

    Give a reason for your answer.

    [2 marks]

    (b) Diagram 15 shows the set up of apparatus for an experiment to determine the empirical

    formula of the oxide of metal Y.

    Diagram 15

    The results are obtained as follows:

    Table 15

    Grey in colour

    Can react with steam

    Reactive metal

    Dry hydrogen

    Oxide of metal Y

    Combustion tube

    Mass of combustion tube + Porcelain dish = 54.30 g

    Mass of combustion tube + Porcelain dish + Oxide of Metal Y = 56.69 g

    Mass of combustion tube + Porcelain dish + Metal Y = 56.37 g

  • Chemistry Perfect Score/X A-Plus Module 2012 27

    (i) Based on the above information, determine the empirical formula of oxide of metal Y

    Given that the relative atomic mass of O = 16, Y = 207

    [4 marks]

    (ii) Describe the steps that should be taken to ensure that all the air in the combustion

    tube has been expelled

    .

    [3 marks]

    (b) Describe an experiment on how to determine the empirical formula of magnesium oxide. In your

    description, state the precautions should be taken during the experiment and show how the empirical

    formula of magnesium oxide is obtained.

    [Relative atomic mass: O = 16; Mg = 24]

    [11 marks]

    16. (a) The following is the chemical formula of a compound.

    SO3

    Name the compound and describe the composition of this compound.

    [3 marks]

    (b) Excess calcium carbonate chips is added to 30 cm3 of 0.5 mol dm

    -3 acid HX.

    The chemical equation below shows the reaction between calcium carbonate and

    acid HX.

    CaCO3 + nHX CaX2 + CO2 + H2O

    Given that the relative atomic mass of C = 12, O = 16 , Ca = 40 and the molar

    volume of any gas is 24 dm3 mol

    -1 at room temperature and pressure.

    (i) Suggest acid HX and name salt CaX2

    Determine the value of n

    [3 marks]

    (ii) Calculate the maximum volume of carbon dioxide gas produced.

    [4 marks]

    (c) You are provided with a sample of M oxide powder. The colour of the M oxide powder is green while

    the colour of metal M is grey. When it is heated with hydrogen, the M oxide is reduced to M metal.

    Based on the information given, describe an experiment to determine the empirical formula of the M oxide. In your description, include the precautions that should be taken and show how the empirical

    formula of M oxide is obtained.

    [Relative atomic mass of O = 16 and M = 56]

    [10 marks]

  • Chemistry Perfect Score/X A-Plus Module 2012 28

    CHEMISTRY MODULE

    SET

    1. Electrochemistry

    2. Oxidation and Reduction

  • Chemistry Perfect Score/X A-Plus Module 2012 29

    SECTION A

    1 Diagram 1 shows the set-up of apparatus of a voltaic cell.

    Diagram 1

    Based on Diagram 1 , answer the following questions.

    (a) What is the energy change that occurs in the voltaic cell?

    ..................................................................................................................................

    [1 mark]

    (b) Write the formula of all ions in copper(II) sulphate solution.

    ..................................................................................................................................

    [1 mark]

    (i) State the name of the negative terminal of the voltaic cell.

    ............................................................................................................................... [1 mark]

    (ii) Give a reason for your answer in (c)(i).

    .....................................................................................................................

    [1 mark]

    (d) (i) State one observation at copper plate.

    .....................................................................................................................

    [1 mark]

    (ii) Write the half equation for the reaction occur at the copper plate.

    .....................................................................................................................

    [1 mark]

    (e) What is the colour change of the copper(II) sulphate solution? Give a reason.

    ..................................................................................................................................

    ..................................................................................................................................

    [2 marks]

    (f) Another experiment is carried out by replacing the zinc plate with P , Q and R metals.

    Table 1 shows the results.

    .Pair of metal Voltage/V Negative terminal

    P/Cu 2.7 P

    Q/Cu 2.0 Q

    R/Cu 0.5 R

    Table 1

    Copper(II) nitrate solution

    Copper plate Zinc plate

    V

  • Chemistry Perfect Score/X A-Plus Module 2012 30

    (i) Arrange P, Q, R and Cu metal in accending order of electropositivity.

    ..................................................................................................................................

    [1 mark]

    (ii) Predict the voltage for pair of Q/R.

    ..................................................................................................................................

    [1 mark]

    2. Diagram 2 shows the set-up of apparatus to investigate the reaction occurred in test tubes X and Y.

    (a) Based on test tube X,

    (i) Name the reaction occurred.

    [1 mark]

    (ii) Write the ionic equation for the reaction.

    [2 marks]

    (iii) Describe a chemical test to verify the product formed.

    ........................................................................................................

    ..........................................................................................................

    [2 marks]

    (b) Based on test tube Y,

    (i) State the observation involved.

    ................................................................................................................

    [1 mark]

    (ii) Experiment is repeated by using copper to replace zinc.

    State the observation involved.

    ..................................................................................................................

    [1 mark]

    (c) Compare the answer in (b) (i) and (b) (ii) and explain why there is a difference in the observation.

    ............................................................................................................................. ................

    .............................................................................................................................................

    [2 marks]

    (d) When iron is exposed to water and oxygen, it rusts easily. State one method to prevent the rusting of

    iron.

    ............................................................................................................................. .............

    [1 mark]

    Test tube X Test tube Y

    Agar solution + Potassium

    hexacyanoferrate(III) solution

    + Phenolphthalein

    Iron nail coiled with zinc

    Diagram 2

    Zinc

    Iron(III) sulphate solution

    Heat

  • Chemistry Perfect Score/X A-Plus Module 2012 31

    SECTION B

    3 Diagram 3.1 shows the set-up of apparatus to investigate the electrolysis of magnesium chloride

    1.0 mol dm-3

    solution.

    Diagram 3.1

    (a) (i) Based on Diagram 3.1;

    State the name of the products at the cathode and the anode.

    Explain the reaction at cathode and anode. Include the following in your explanation:

    List the ions attracted to cathode and anode.

    State the ions selectively discharged at cathode and anode.

    The reason why the ions are selectively discharged.

    Half equation for the reaction at cathode and anode. [10 marks]

    (ii) Predict the product at anode and cathode if magnesium chloride 1.0 mol dm-3

    solution

    is replaced by magnesium chloride 0.0001 mol dm-3

    solution.

    [2 marks]

    (b) Diagram 3.2 shows the set up of apparatus when cell X is combined with cell Y.

    Compare and contrast cell X and cell Y in terms of following:

    Types of cells

    Energy changes

    Name of electrodes

    Ions in the electrolyte

    Half equations

    Observations . [8 marks]

    Copper plate

    Copper(II) sulphate

    solution

    Magnesium

    plate

    Cell X Cell Y

    Copper plate

    Diagram 3.2

    V

    Magnesium chloride 1.0 mol dm-3

    A

    Carbon

    electrodes

  • Chemistry Perfect Score/X A-Plus Module 2012 32

    4 (a) The following are the formulae of two compounds.

    Na2O PbO2

    (i) Based on the two formulae , state the oxidation number for sodium and lead. [ 2 marks]

    (ii) State the name of the compounds based on the IUPAC nomenclature. [ 2 marks]

    (b) Diagram 4 shows the observation of two experiment to study the effect of metal P and metal Q on the

    rusting of iron.

    Experiment Observation

    Experiment 1

    Large amount of dark blue precipitate

    Experiment 2

    No dark blue precipitate.

    Solution turns pink.

    Diagram 4

    (i) Suggest metal P and metal Q. (ii) Explain the observations and write the chemical equation for the reaction in the experiment 1

    and experiment 2.

    [ 10 marks]

    (c) The equation shows a redox reaction. M is a metal.

    X(s) + CuSO4 (aq) XSO4 (aq) + Cu(s)

    Suggest metal X and explain the redox reaction in terms of the transfer of electrons .

    [6 marks]

    SECTION C

    5 Diagram 5 shows the set-up of apparatus for electrolysis of 1.0 mol dm-3

    sodium sulphate solution.

    Diagram 5

    (a) State the name of gas produced at electrode X and electrode Y. [2 marks]

    Carbon electrode Y Carbon electrode X

    1.0 moldm-3

    sodium

    sulphate solution

  • Chemistry Perfect Score/X A-Plus Module 2012 33

    (b) Explain the reaction at electrode X and electrode Y. Include the following inyour explanation.

    List of ion attracted to each electrodes, X and Y.

    State the name of the ions selectively discharged at each electrode.

    The reason why the ion are selectively discharged. [5 marks]

    (c) When sodium sulphate solution is replaced by a solution of substance Z with same concentration, the equal gas produced at electrode X and electrode Y .

    Suggest the substance Z. Write the half equation for the reaction at electrode X.

    [3 marks]

    (d) Zinc is placed above metal A in the electrochemical series. Zinc and metal A can be used to build a chemical cell, using suitable apparatus and the following chemicals ;

    Zinc

    Zinc nitrate solution

    Metal A

    A nitrate solution

    By naming metal A and A nitrate solution, describe how you build the chemical cell.

    Include a labelled diagram in your answer.

    On your diagram, mark the direction of electron flow, the positive terminal and the negative

    terminal.

    [ 10 marks]

    6 (a) The following are the equations of two reactions:

    Determine which reaction is a redox reaction.

    Explain your answer in terms of oxidation number.

    [4 marks]

    (b) Table 6 shows the observations of two experiments to determine the position of carbon in the

    reactivity series of metal.

    Experiment Reactants Observation

    I Carbon + oxide of metal P A flame spreads to the whole mixture.

    A brown residue is formed.

    II Carbon + oxide of metal Q No change

    III Carbon + oxide of metal R A glow spreads to the whole mixture. A

    grey residue is formed.

    Based on observations in Table 6, arrange the reactivity of metals P, Q, and R in descending order.

    Explain your answer.

    [6 marks]

    (c)

    By using a named metal as a reducing agent and a named halogen as an oxidising agent, describe

    briefly how you would carry out these two conversion.

    Describe a test to show that each conversion has taken place.

    [ 10 marks]

    Reaction I : NaOH + HCl NaCl + H2O

    Reaction II : Mg + Zn(NO3)2 Mg(NO3)2 + Zn

    Table 6

    Iron(II) ions can be converted to iron(III) ions and iron(III) ions can be converted back to iron(II) ions.

  • Chemistry Perfect Score/X A-Plus Module 2012 34

    CHEMISTRY MODULE

    SET

    1. Acids and Bases 2. Salts 3. Rate of reaction

    4. Thermochemistry

  • Chemistry Perfect Score/X A-Plus Module 2012 35

    SECTION A

    1. Diagram 1 shows four test tubes labeled A,B,C and D which are used to study the relationship between pH value of acid and alkali with the molarity.

    pH paper

    A B C D

    5 cm3HCl 5 cm

    3HCl 5 cm

    3 NaOH 5 cm

    3 NaOH

    0.1 mol dm-3

    0.01 mol dm-3

    0.1 mol dm-3

    0.01 moldm-3

    (a) Determine which solution has

    (i) highest pH value.

    ` ......... [1 mark]

    (ii) lowest pH value. Give a reason for your answer.

    ............. [2 marks]

    (b) If the hydrochloric acid in test tube B is replaced with 5 cm3 of 0 .01 mol dm

    -3ethanoic acid,

    predict the pH value of the solution. Explain your answer

    .....

    . [3 marks]

    (c) Excess of magnesium powder is added to 5 cm3 of 0.1moldm

    -3 hydrochloric acid in test tube A

    (i) State the name of the products formed.

    .

    ..... [1 mark]

    (ii) Write the chemical equation for the reaction in test tube A

    [1 mark]

    (iii) Calculate volume of hydrogen gas released at room conditions in test tube A

    [1 mol of gas occupies 24 dm3 at room conditions]

    [3 marks]

    Diagram 1

  • Chemistry Perfect Score/X A-Plus Module 2012 36

    Add water

    (d) If the solution in test tube C is added to lead(II) nitrate solution. State the observation from the

    reaction.

    . [1 mark]

    2. (a) Diagram 2.1 shows the pH value of glacial ethanoic acid in solvent P and solvent Q respectively.

    (i) Suggest solvent P and solvent Q.

    Solvent P: ....

    Solvent Q: . [2 marks]

    (ii) If magnesium ribbon is added into beaker containing glacial ethanoic acid and solvent P, what can be observed?

    . [1 mark]

    (iii) Explain why ethanoic acid in solvent P and solvent Q has different the pH value.

    .

    .

    .

    ... [3 marks]

    (b) Diagram 2.2 shows the concentration of hydrochloric acid in volumetric flask when a certain

    volume of hydrochloric from the beaker is transferred to the volumetric flask and added with

    water

    7.0 4.8

    Glacial ethanoic acid

    + solvent P Glacial ethanoic acid +

    solvent Q

    100 cm3 of 0.5 moldm

    -3 hydrochloric acid

    Diagram 2.1

    Diagram 2.2 250 cm

    3 of 0.04 moldm

    -3 hydrochloric acid

  • Chemistry Perfect Score/X A-Plus Module 2012 37

    (i) What happen to the pH value of the hydrochloric acid when water is added to the acid?

    Give a reason for your answer.

    .

    . [2 marks]

    (ii) Calculate the volume of hydrochloric acid that is needed to prepare 250cm3 of 0.04 mol dm-3 hydrochloric acid.

    [2 marks]

    3. A student carried out an experiment to investigate the properties of three solutions. Diagram 3 shows the results of the experiments.

    Test tube P Q R Set-up of

    apparatus

    Observation

    The red litmus

    paper turned blue. No change

    Diagram 3

    (a) What is meant by strong alkali?

    ............................................................................................................................. ..........

    [1 mark]

    (b) What is the property of the solution in test tube P?

    .......................................................................................................................................

    [1 mark]

    (c) What are the types of particles that exist in the test tubes P and Q?

    Particles in the test tube P: ..........................................................................................

    Particles in the test tube Q: .........................................................................................

    [2 marks]

    (d) Is there any changes of colour of the litmus paper in test tube Q? Give a reason to your answer.

    ............................................................................................................................. .........

    ......................................................................................................................................

    [2 marks]

    Ammonia gas

    dissolved in

    water

    Red litmus

    Paper

    Ammonia gas

    dissolved in

    propanone

    Red litmus

    Paper

    Hydrogen

    chloride gas

    dissolved in water

    Magnesium

  • Chemistry Perfect Score/X A-Plus Module 2012 38

    (e) (i) What can be observed in test tube R?

    ............................................................................................................................. .........

    [1 mark]

    (ii) Write a chemical equation for the reaction in test tube R.

    .......................................................................................................................................

    [2 marks]

    (iii) 2.4 g of magnesium is reacted completely with the solution in test tube R.

    Calculate the volume of the hydrogen gas produced at room condition

    [Relative atomic mass: Mg,24; 1 mol of gas occupies 24 dm3 at room conditions]

    [2 marks]

    4 Diagram 4 shows the apparatus set-upfor the neutralisation reaction between sulphuric acid and

    potassium hydroxide solution for preparation of salt X.

    Diagram 4

    (a) (i) State the colour change of the solution in the conical flask at the end point.

    . [1 mark]

    (ii) Write a chemical equation for the above reaction.

    . [2 marks]

    (iii) Calculate the concentration of potassium hydroxide used.

    [2 marks]

    (b) (i) State the name of salt X.

    ..

    25.0 cm3

    potassium hydroxide

    solution + phenolphthalein

    indicator

    15 cm3of 0.1mol dm

    -3

    sulphuric acid

  • Chemistry Perfect Score/X A-Plus Module 2012 39

    [1 marks]

    (ii) Calculate the maximum mass of salt X formed.

    [Molar mass of salt X = 174 g mol-1

    ]

    [3 marks]

    (c) (i) The experiment is repeated with 0.1 mol dm-3 nitric acid to replace sulphuric acid. Predict the volume of nitric acid needed to neutralize completely potassium hydroxide

    .. [1 mark]

    (iii) Explain your answer in (c) (i).

    ......................................................................................................................................................

    ............................................................................................................................. .........................

    [2marks]

    5. Diagram 5 shows a series reaction of copper compound.

    (a) Copper(II) nitrate solution reacts with sodium carbonate solution to form copper(II) carbonate

    precipitate.

    (i) What is the colour of copper(II) carbonate?

    ............. [1 mark]

    (ii) State the name of the reaction.

    ............................................................................................................................. ............................

    [1 mark]

    (b) Heating of copper(II) carbonate produces copper(II) oxide and gas X.

    (i) State the name of gas X.

    .. [1 mark]

    (ii) Write the chemical equation of the reaction.

    ................................................................... [2 mark]

    Copper(II)

    carbonate

    Copper(II)

    oxide

    Sodium carbonate Copper(II)

    nitrate

    Copper(II) sulphate

    Diagram 5

    Acid Y

    Heat Gas X +

  • Chemistry Perfect Score/X A-Plus Module 2012 40

    (iv) Draw a labeled diagram for the heating of copper(II) carbonate to produce copper(II) oxide and gas X. In your diagram show how gas X is tested.

    [2 marks]

    (c) Copper(II) carbonate reacts with acid Y to produce copper(II) sulphate. The chemical equation is

    shown below.

    CuCO3 + Acid Y CuSO4 + CO2 + H2O (i) What is acid Y?

    [1 mark]

    (ii) 12.4 g copper(II) carbonate reacts completely with excess acid Y.

    Calculate the mass of copper(II) sulphate formed.

    [Relative atomic mass: C = 12, O=16 , S = 32, Cu = 64]

    [3 marks]

    6. Three experiments were conducted to investigate factors affecting the rate of reaction. The results are shown in the Table 6

    Experiment Reactants Temperature / 0C

    Time taken for all the

    magnesium to dissolve/s

    I 0.4g magnesium ribbon and 50 cm

    3

    1 moldm-3

    hydrochloric acid 30 100

    II 0.4g magnesium powder and 50 cm

    3

    1 moldm-3

    hydrochloric acid 30 60

    III

    0.4g magnesium ribbon and 50 cm3

    1 moldm-3

    hydrochloric acid and copper(II)

    sulphate solution

    30 45

    Table 6

    (a) Write a chemical equation to show the reaction between magnesium and hydrochloric acid.

    [2 marks]

    (b) Calculate the number of mole of

    (i) Magnesium

    [Relative atomic mass of Mg = 24]

    [1 mark]

    (ii) Hydrochloric acid

    [1 mark]

  • Chemistry Perfect Score/X A-Plus Module 2012 41

    (c) If hydrochloric acid used is excess, calculate the maximum volume of hydrogen gas produce at

    room temperature and pressure.

    [1 mole of gas occupies the volume of 24 dm3 at room temperature and pressure]

    [2 marks]

    (d) Calculate the average rate of reaction for

    (i) Experiment I

    [1 mark]

    (ii) Experiment II.

    [1 mark]

    (iii) What is the purpose of using copper(II) sulphate?

    . [1 mark]

    (f) The factor that affects the rate of reaction in this experiment is total surface area and the use of

    catalyst. State two other factors that affect the rate reaction in this experiment.

    .. [2 marks]

    7. Diagram 7 shows two experiments to investigate one of the factors that affect the rate of reaction between

    zinc and hydrochloric acid

    Diagram 7

    (a) (i) Based on Diagram 7, state the factor that affect the rate of reaction in this experiment.

    .

    [1 mark]

    50 cm3 1 mol dm-3HCl

    Hydrogen gas

    Excess zinc

    granules

    Experiment I

    50 cm3 1 mol dm-3HCl + copper(II) sulphate

    solution

    Hydrogen gas

    Excess zinc

    granules

    Experiment II

  • Chemistry Perfect Score/X A-Plus Module 2012 42

    (ii) Besides measuring the change of volume of gas released at certain time interval, suggest another

    measurable change to determine the rate of reaction?

    ..

    [1 mark]

    (b) In Experiment II, 2.0 cm3 0.5 moldm-3copper(II) sulphate solution is added. The maximum volume of

    hydrogen gas released in Experiment I is V cm3.

    (i) Compare the volume of gas released in Experiment I and Experiment II.

    Give a reason for your answer.

    ..

    .

    [2 marks]

    (ii) The graph of volume of hydrogen gas released against time in Experiment I is shown below.

    Sketch the curve for Experiment II on the same axes in the graph above.

    [2 marks]

    (iii) With reference to collision theory, explain how copper(II) sulphate solution affect the rate of

    reaction in this experiment.

    [3 marks]

    (c) Table 7.1 shows three experiments done by a student.

    Experiment Reactants

    A Excess calcium carbonate chips + 25 cm

    3 1.0 mol dm

    -3

    hydrochloric acid

    B Excess calcium carbonate chips + 25 cm

    3 0.5 mol dm

    -3

    hydrochloric acid

    C Excess calcium carbonate chips + 100 cm

    3 0.5 mol dm

    -3

    hydrochloric acid

    Table 7.1

    Time / s

    Volume of gas

    released/ cm3 Key : Experiment I :

    Experiment II : ..

  • Chemistry Perfect Score/X A-Plus Module 2012 43

    The graph of volume of carbon dioxide released against time is sketched as shown in graph 7

    Based on the above table and graph, determine which curve represents the results for experiment B

    and C. Write your answers in the boxes provided.

    [1 mark]

    8. An experiment is conducted to study the heat of displacement for reaction between copper(II) sulphate

    and excess magnesium powder. 50.0 cm3 of 0.5 mol dm

    -3 copper(II) sulphate solution is poured into a

    polystyrene cup and the initial temperature is recorded. The excess magnesium powder is added to the

    same polystyrene cup. The mixture is stirred slowly and the highest temperature is recorded.

    Initial temperature of copper(II) sulphate solution = 28.5 oC

    Highest temperature of mixture = 33.5 oC

    [Relative atomic mass : Cu=64; S=32; O=16; Zn= 65;

    (a) What is the meaning of heat of displacement in this experiment?

    ............................................................................................................................

    ............................................................................................................................ [1 mark]

    (b) Why does zinc in the form of powder is used in this experiment?

    [1 mark]

    (c) Write the ionic equation for the reaction in this experiment.

    ............................................................................................................................

    [2 marks]

    (d) (i) Based on the experiment, calculate the heat energy released.

    [1 mark]

    (ii) number of mole of copper(II) sulphate that has reacted

    [1 mark]

    (iii) heat of displacement in this reaction

    [2 marks]

    (e) Draw an energy level diagram for the reaction.

    [3 marks]

    Time/s

    Volume of

    carbon

    dioxide

    /cm3 Experiment

    A

    Graph 7

  • Chemistry Perfect Score/X A-Plus Module 2012 44

    5 g of zinc powder

    50 cm3 of 0.2 mol dm

    -3

    copper(II) sulphate solution

    Plastic cup

    (f) Why polystyrene cup is used in this experiment?

    [1 mark]

    9. Diagram 9 shows the apparatus set-up to determine heat of displacement of copper by using zinc

    powder. The result of the experiment is recorded in the Table 9.

    Diagram 9

    Initial temperature of copper(II) sulphate solution (oC) 30.0

    Highest temperature of the mixture (oC) 38.0

    Table 9

    (a) What is the meaning of heat of displacement?

    [1 mark]

    (b)

    (c)

    Why plastic cup is used in this experiment.

    [1 mark]

    State the type of reaction that occurs based on the temperature change.

    [1 mark]

    (d) Calculate :

    (i) the heat change for the reaction

    [Specific heat capacity of solution = 4.2 J g-1

    oC

    -1; Density of solution = 1 g cm

    -3]

    [1 mark]

    (ii) the heat of displacement for the reaction.

    [2 marks]

    (e) Draw energy level diagram for the reaction.

    [3 marks]

  • Chemistry Perfect Score/X A-Plus Module 2012 45

    (f) Experiment is repeated by using 100 cm3 of 0.2 mol dm

    -3 of copper(II) sulphate solution.

    (i) Predict the temperature change in the experiment.

    .

    ...

    [1 mark]

    (ii) Explain your answer in (e) (i).

    ...

    ...

    ... [2 marks]

    10. The equation for combustion of propanol in excess oxygen is given below.

    (a) What is meant by heat of combustion in this reaction?

    .......................................... [1 mark]

    (b) State two information that can be obtained from the equation

    ...........................................

    [2 mark]

    (c) Heat given out from the complete combustion of 1.2 g propanol is used to heat 200 cm3 of water.

    Calculate:

    (i) The heat energy given out in the reaction. [Molar mass of propanol, C3H7OH = 60 gmol

    -1]

    [2 marks]

    (ii) The temperature change in the reaction.

    [Spesific heat capacity of water = 4.2 Jg-1 o

    C-1

    ; Density of water = 1 gcm-3

    ]

    [2 marks]

    (d) Draw the energy level diagram for this reaction.

    [3 marks]

    C3H7OH + 9 O2 3CO2 + 4H2O , H = -2015 kJ mol-1

    2

    2

  • Chemistry Perfect Score/X A-Plus Module 2012 46

    (e) The value of the heat of combustion of propanol obtained from the experiment is less than the

    theoretical value. Suggest one precaution step that should be taken in order to get a more accurate result.

    ............................................................................................................................................................

    [1 mark]

    (f) Table 10 show s the molecular formula and the heat of combustion for methanol and ethanol.

    Alcohol Molecular formula Heat of combustion/kJmol-1

    Methanol CH3OH -728

    Ethanol C2H5OH -1376

    Based on the information in Table 10, explain why there is a difference in the value of heat of

    combustion between methanol and ethanol.

    ............................................................................................................................. .............

    ..........................................................................................................................................

    ............................................................................................................................. .............

    ..........................................................................................................................................

    [3 marks]

    SECTION B

    11. (a) A student has carried out an experiment to construct an ionic equation for the formation of lead(II)

    iodide. Seven test tubes of the same size were labeled 1 to 7. A fixed volume of 5.0 cm3 of 1.0 mol

    dm-3

    potassium iodide solution was poured in each test tube. The volume of 1.0 mol dm-3

    lead(II)

    nitrate solution that added are shown in Table 11. The height of precipitate formed in each test tube

    was measured. The results are shown in Table 11.

    Table 11

    (i) Based on Table 11, plot a graph of the height of precipitate against volume of lead(II) nitrate solution.

    [3 marks]

    (ii) Determine the number of moles of lead(II) ions and iodide ions that are required for the formation of lead(II) iodide. Your answer should consist of the following:

    the volume of lead(II) nitrate solution that had reacted completely with 5.0 cm3 of 1.0 mol dm

    -3 potassium iodide

    calclate the number of moles of lead(II) ions and iodide ions

    calculate the number of moles of iodide ions that has reacted with 1 mol of lead(II) ions.

    write the ionic equation for the formation of lead(II) iodide. [7 marks]

    Test tube 1 2 3 4 5 6 7

    Volume of 1.0 moldm-3

    lead(II)

    nitrate solution / cm3

    0.5 1.0 1.5 2.0 2.5 3.0 3.5

    Height of precipitate /cm 1.1 2.2 3.4 4.4 5.5 5.5 5.5

    Table 10

  • Chemistry Perfect Score/X A-Plus Module 2012 47

    (b) Diagram 11 shows the flow chart of reaction of salt J. X oxide which is brown when hot and yellow when cold is formed when salt J is heated strongly. Salt J dissolves in water to form colourless

    solution. The solution formed is tested with potassium iodide, KI solution.

    + +

    H2O

    Diagram 11

    Based on the information in Diagram 11:

    (i) Identify salt J, X oxide, brown gas Y, colourless gas Z and yellow precipitate L. [5 marks]

    (ii) State the name of the anion present in salt J. Then describe one chemical test to determine the presence of anion in salt J.

    [5 marks]

    12. Diagram 12.1 shows a series of reaction for salt S which is a green colour compound. Salt S is heated strongly to produce black residue of compound T and gas U.

    Compound T reacts with sulphuric acid to form blue solution of compound W.

    Diagram 12.1

    Based on Diargram 12.1:

    (a) (i) Suggest one formula of the anion in salt S.

    [1 mark]

    (ii) Identify salt S, compound T, gas U and compound W.

    [4 marks]

    (b) Write a chemical equation for the reaction between compound T and sulphuric acid.

    [2 marks]

    (c) Compound W is a soluble salt. Describe chemical test to verify the cation and anion in compound W.

    [5 marks]

    Salt J X Oxide Brown gas Y Colourless gas Z

    Salt J solution Yellow precipitate L

    Potassium iodide

    solution

    Heat + Salt S Compound T Gas U

    Compound W

    + H2SO4

    Lime water turns cloudy

    Pass through

    lime water

  • Chemistry Perfect Score/X A-Plus Module 2012 48

    (d) Diagram 12.2 shows the chemical equation for the reaction between blue solution of compound W and

    barium nitrate solution.

    Diagram 12.2

    Based on Diagram 12.2:

    (i) State the name of salt X and salt Y. [2 marks]

    (ii) State one observation and name the type of reaction occurred.

    [2 marks]

    (iii) Compound W reacts with 50 cm3 of 0.1 mol dm-3 barium nitrate solution.

    Write the ionic equation for the reaction and calculate the mass of salt X produced.

    [Relative molecular mass of salt X: 233]

    [4 marks]

    13 (a) Table 13 shows the incomplete observation for two experiments to construct balanced chemical

    equation.

    Experiment Procedure Observation

    A Copper(II) carbonate is heated and the gas

    produced is passed through lime water..

    Green solid turns black.

    The lime water turns milky.

    B Potassium iodide solution is added to lead(II)

    nitrate solution.

    Table 13

    (i) Based on the observation, state the name of the products in experiment A and write the chemical equation for the reaction.

    [3 marks ]

    (ii) State one observation in experiment B and state the name of the products formed. Write the chemical equation for the reaction.

    [4 marks ]

    (b) You are given aluminium nitrate solution and zinc nitrate solution.

    Describe chemical tests that can be used to verify the cations and a