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Chemistry Perfect Score Module 2011 1 BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH DAN SEKOLAH KECEMERLANGAN MODUL PERFECT SCORE SEKOLAH BERASRAMA PENUH TAHUN 2011 CHEMISTRY Pn. Wan Noor Afifah Binti Wan Yusoff (Ketua) SBPI GOMBAK Pn. Aishah Peong Binti Abdullah SBPI TEMERLOH Pn. Norini Binti Jaafar SEKOLAH SULTAN ALAM SHAH Pn. Noraini Binti Zakaria SMS SULTAN MOHAMAD JIWA Pn. Rossita Binti Radzak SMS TUANKU MUNAWIR En Che Malik Bin Mamat SBPI BATU RAKIT En Jong Kak Ying SMS KUCHING En Ooi Yoong Seang SMS MUAR Pn Sa’adah Binti Mohayuddin SMS SERI PUTERI Pn Faridah Bt Hamat SMS TUANKU MUNAWWIR

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    Chemistry Perfect Score Module 2011 1

    BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUHDAN SEKOLAH KECEMERLANGAN

    MODUL PERFECT SCORE SEKOLAH BERASRAMA PENUH

    TAHUN 2011

    CHEMISTRY

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

    Pn. Aishah Peong Binti Abdullah SBPI TEMERLOH

    Pn. Norini Binti Jaafar SEKOLAH SULTAN ALAM SHAH

    Pn. Noraini Binti Zakaria SMS SULTAN MOHAMAD JIWA

    Pn. Rossita Binti Radzak SMS TUANKU MUNAWIREn Che Malik Bin Mamat SBPI BATU RAKIT

    En Jong Kak Ying SMS KUCHINGEn Ooi Yoong Seang SMS MUAR

    Pn Saadah Binti Mohayuddin SMS SERI PUTERI

    Pn Faridah Bt Hamat SMS TUANKU MUNAWWIR

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    Chemistry Perfect Score Module 2011 2

    CHEMISTRY PERFECT SCORE MODULE 2011 CONTENT

    1 Guidelines & Anwering Techniques

    Format of an instrument of chemistryConstruct requirementGuidelines for answering paper 1Guidelines for answering paper 2Guidelines for answering paper 3The common command words in paper 2

    2 Set 1

    The structure of AtomChemical Formulae and equationsPeriodic Table of ElementsChemical Bonds

    3 Set 2ElectrochemistryOxidation and Reduction

    4 Set 3

    Acids and BasesSaltsRate of reactionThermochemistry

    5 Set 4Carbon compoundsManufactured Substance in IndustryChemicals for Consumers

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

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    Chemistry Perfect Score Module 2011 3

    CHEMISTRYPERFECT SCORE MODULE

    GUIDELINES

    ANSWERING TECHNIQUES

    CHEMISTRY SPM

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    Chemistry Perfect Score Module 2011 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 ItemSection B :Essay restricted response ItemSection C :Essay extended response Item

    Subjective Item :Structured ItemExtended 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 3Knowledge 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 - - 50Total 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 atom2. Chemical Formulae And Equations3. Periodic Table4. 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 diagram6. Writing chemical equation( balanced equation, ionic equation, half equation)

    3.3 Try to get :-40 marks above for paper 160 marks above for paper 240 marks above for paper 3 (Total = 180/2 =80 , A+ in SPM)

    4.0 GUIDELINE FOR ANSWERING PAPER 1

    4.1 Paper 1 questions test students on1. 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 weak20 25 - weak26 30 - average31 39 - good40 45 - very good46 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.

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    Chemistry Perfect Score Module 2011 5

    5.0 GUIDELINE FOR ANSWERING PAPER 2 (STRUCTURE AND ESSAY)5.1 Paper 2 questions test student on

    1. Knowledge2. understanding3. analyzing4. 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. Diagram2. Procedure3. Observation/example/data/calculation/equation/sketch of graph/conclusion

    II. Type 2Describe an experiment( The diagram will support your answer.)

    1. No mark is allocated for a diagram2. Procedures3. Observation/example/calculation/equation/sketch of graph/conclusion

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

    2. Observation3. Conclusion

    6.0 GUIDELINE FOR ANSWERING PAPER 36.1 Structure Question 1/2 test the mastery of 11 Scientific Skills

    1. Observing2. Classifying3. Inferring4. Measuring (burette , stopwatch, thermometer, voltmeter)5. Predicting6. Communicating( e.g construct table and draw graph)7. Space-Time Relationship8. Interpreting Data9. Defining Operationally10. Controlling Variables11. Hypothesizing

    Each answer is allocated mark as follows: 3 marks/2 marks/1 mark/0 Score : 11 X 3 = 33Example of operational definition:1. what you do2. what you observe correctlyExample:

    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 todisappear from sight is shorter.

    3. When iron nail is coiled with copper and immersed into jelly mixed with potassium hexacyanoferrate(III) and phenolphthaleinsolution, blue spot/colouration is formed.

    Operational definition for What you do What is observed1. Rusting of iron When an iron nail coiled with a less

    electropositive metal is immersed in hotagar-agar added with potassiumhexacyanoferrate (III) solution,

    Blue spots are formed

    2. Coagulation of latex When acid is added to latex White solid is formed3. Reactivity of Group 1

    elementsWhen a metal which is lower in Group 1 isput in a basin half filled with water

    Brighter flame is formed

    4. Precipitation of silver chloride

    When silver nitrate solution is added tosodium chloride solution

    White solid is formed

    5. Voltaic cell When two different metals are dipped into anelectrolyte

    The needle of thevoltmeter deflects

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

    Blue litmus paper turnsred

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    Chemistry Perfect Score Module 2011 6

    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 marks2. 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

    6.2 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 variables3. Statement of the hypothesis4. List of substances/material and apparatus should be separated5. Procedure of the experiment6. 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 tothe manipulated variables.

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

    Example : Rate of reaction stop watchTermochemistry - 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 procedureII. 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.

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    Chemistry Perfect Score Module 2011 7

    7.0 THE COMMON COMMAND WORDS IN PAPER 2 & PAPER 3 CHEMISTRYThe 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 thename

    (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 theobservation

    (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 releasedIndicate 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 colourlessCorrect 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 meaningExample: What is meant by hydrocarbon.Wrong answer: A compound that contains carbon and hydrogenCorrect answer : A compound that contains carbon hydrogen only

    Describe chemicaltest(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 cm 3 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- A reddish brown precipitate formed. ...........1- Fe 3+ 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 anexperiment( 8 - 10 marks)(Paper 2)

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

    - 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 anexperiment( 17 marks)( Paper 3)

    Answer the question according the requirement :Problem statement/Aim of experimentHyphotesisVariablesList of substances and apparatusProcedureTabulation of data

    Note: For question 3, unlike PEKA report students only need to answer according to what is stated inthe question.

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

    Can be obtained from the diagram

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    Chemistry Perfect Score Module 2011 8

    Describe theprocess Describe thestructure . 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 factsExample : 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 i tems/situationsExample : 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 theapparatus(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 toshow the bonding

    formed in thecompound(Paper 2)

    (i)Ionic compound The number of electrons in each shell is correct, 2 electrons in the first shelland 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 compoundThe number of electrons in each shell is correct, 2 electrons in the f irst shell and8 electrons in the second and third shell.The number of atoms sharing pair of electrons is correct.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 unitChoose suitable scale, the size of the graph should be at least of the size of the graphpaper.Plot all the points correctlySmooth 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 tangentCalculate the gradient of the tangent

    Draw the energylevel 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 thearrangement 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 notoverlap.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 chemicalequation

    (Paper 2 & 3)

    Write the balanced chemical equationDifferentiate :

    (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 takenGive final answer with unit.

    Classify(Paper 3)

    Draw table to represent the classification.

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    Chemistry Perfect Score Module 2011 9

    CHEMISTRY PERFECT SCORE MODULE

    SET

    1. The Structure of Atom2. Chemical Formulae and Equations

    3. Periodic Table of Elements4. Chemical Bonds

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    Chemistry Perfect Score Module 2011 10

    PAPER 2 : SECTION A [STRUCTURE]

    1 Diagram 1 shows the apparatus set-up used in an experiment to determine the empirical formula of anoxide of copper.

    DIAGRAM 1

    The following data was obtained:

    Mass of combustion tube + porcelain dish = 25.30 g

    Mass of combustion tube + porcelain dish + copper(II) oxide = 53.30 gMass of combustion tube + porcelain dish + copper = 47.70 g

    (a) What is meant by empirical formula?

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

    .. [1 mark]

    (b) Write a chemical equation for the reaction used to produce hydrogen gas.

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

    (c) How to ensure that all the copper oxide is completely reacted?

    .. ....

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

    (d) Based on the data given, determine the empirical formula of the copper oxide.

    [4 marks]

    (e) Write the chemical equation for the reaction between hydrogen and the oxide of copper.

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

    (f) After the reaction is completed, hydrogen gas is allowed to flow continuously until the copperis cooled to room temperature. Explain why .

    ......

    ...... [1 marks]

    Dry hydrogengas

    Heat

    Copper oxide

    Burning of excess

    hydrogen

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    Chemistry Perfect Score Module 2011 11

    (g) The empirical formula for magnesium oxide can be determined by direct heating of magnesium.Draw a labeled diagram to show apparatus set-up to carry out this experiment.

    [ 2 marks]

    2 (a) 70.2 g of aluminium carbonate decomposed easily when heated to produce aluminium oxide basedon the following equation.

    [Relative atomic mass: Al: 27 ; C: 12; O: 16; 1 mole of gas occupied 24 dm 3 at room condition]

    (i) Write the formula of Aluminium carbonate.

    ..... [1 mark]

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

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

    (iii) Calculate the mass of aluminium oxide that is produced.

    [3 marks]

    (iv) Calculate the volume of carbon dioxide gas produced at room conditions .

    [3 marks]

    ................(s) Al 2O3(s) + CO 2(g)

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    Chemistry Perfect Score Module 2011 12

    (b) Table 2 shows an experiment to investigate the effect of heat on metal carbonate.

    Diagram Procedure Observation

    Metal carbonate is heatedand the gas produced ispassed through lime water.

    White solid turns yellowwhen hot and whitewhen cool.

    The lime water turnscloudy.

    Table 2

    Based on the experiment:

    (i) Name the metal carbonate used.

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

    (ii) State the name of the products formed.

    .... [1 mark]

    (iii) Write a chemical equation for the reaction.

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

    3 Table 3 shows the proton number and the number of neutrons for atoms P, Q, R and S.

    Table 3(a) (i) What is meant by the proton number ?

    ..... [1 mark]

    (ii) What is the nucleon number of atom P?

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

    (b) Write the symbol for atom Q in the form

    ... [1 mark]

    (c) Which atoms have the same number of valence electrons?

    [1 mark]

    Atom Proton number Number of neutrons

    P 3 4 Q 16 17 R 16 16

    S 19 20

    Heat

    Metal carbonate

    Lime water

    XA

    Z

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    Chemistry Perfect Score Module 2011 13

    (d) (i) Which atoms are isotopes?

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

    (ii) State a reason for your answer in (d) (i).

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

    (e) Diagram 3 shows a graph of temperature against time of substance X when it is heated until itboils.

    (i) What is the melting point of substance X?

    . [1 mark]

    (ii) Complete the table below by stating the physical state of substance X at the section ABand DE.

    Section Physical state

    AB

    DE

    [1 mark](iii) Explain why the temperature remains constant from t1 to t2.

    [2 marks]

    Diagram 3

    C

    E

    Temperature / oC

    B

    D

    F

    A

    Time / s

    777

    63

    t1 t2 t3 t4

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    Chemistry Perfect Score Module 2011 14

    4 Table 4 shows the proton number of a few elements in Period 3.

    Element Sodium Magnesium Aluminium Chlorine Argon

    Proton number 11 12 13 17 18 Table 4

    Based on Table 4, answer the following questions:

    (a) State two elements which are metals.

    [1 mark]

    (b) Chlorine is in Group 17 in the Periodic Table of Elements. What is another name for group 17?

    . [1 mark]

    (c) Write the electron arrangement of aluminium atom.

    .. [1 mark]

    (d) (i) Arrange the element in Table 4 according to descending order of atomic sizes.

    . [1 mark]

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

    [2 marks]

    (e) When sodium is burnt in chlorine gas, sodium chloride is formed.

    (i) State one observation for the reaction.

    [1 mark]

    (ii) Write the chemical equation for the reaction.

    [2 marks]

    (iii) State one physical property of sodium chloride.

    [1 mark]

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    Chemistry Perfect Score Module 2011 15

    5 Diagram 5 shows the symbols of atom of elements U, V, W and X.

    U73

    V126

    W199

    X2010

    Diagram 5

    (a) (i) Which element is an inert gas?

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

    [1 mark](ii) Give a reason for your answer in (a) (i).

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

    (b) Element W exists as diatomic molecule.State the type of chemical bond in molecule W.

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

    (c) Element V can react with element W to form a compound.(i) Write the chemical formula for the compound formed.

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

    (ii) Draw the electron arrangement for the compound formed.

    [2 marks]

    (iii) State one physical property for the compound formed.

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

    (d) Element U reacts with element W to form a compound .

    (i) State the type of the compound produced.

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

    (ii) Explain briefly how the compound is formed......................................................................................................................................................

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

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

    [3 marks](iii) Draw the electron arrangement for the compound formed.

    [2 marks]

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    Chemistry Perfect Score Module 2011 16

    X YY

    PAPER 2: SECTION B [ESSAY]

    6 (a) Diagram 6.1 shows the electron arrangement for atom of an element from Group 17 in thePeriodic Table of Element.

    Diagram 6.1Based on Diagram 6.1,(i) Write the electron arrangement for the atom and state the name of the element.

    [2 marks](ii) Write a chemical equation for the reaction between the element and iron.

    [2 marks](b) Table 7.2 shows the observation of the reaction between Group 1 elements X , Y and Z with

    water.

    Group I element Observation

    X [Proton number =3]

    X moves slowly o n the water surface with a soft hiss sound. A colourless solution that turns red litmus paper blue is formed.

    Y [Proton number =11]

    Y moves rapidly and randomly on the water surface with a hisssound. A colourless solution that turns red litmus paper blue isformed..

    Z [Proton number =19]

    Z burns with a reddish-purple flame, moves very rapidly andrandomly on the water surface with hiss and pop sound. Acolourless solution that turns red litmus paper blue is formed..

    Table 6.2Based on Table 6.2

    (i) Arrange X, Y and Z in descending order of reactivity of Group I elements towards water.Compare and explain the reactivity X and Z with water.

    [6 marks]

    (ii) Compare the chemical property of X, Y and Z. Give a reason for your answer.[2 marks]

    (c) Diagram 6.3 shows the electron arrangement of a molecule XY 2.

    Diagram 6.3Based on Diagram 6.3, write the electron arrangement for atom element X and element Y.Explain briefly how the molecule is formed from atom X and atom Y.Explain the position of element Y in the Period Table of Element.

    [8 marks]

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    Chemistry Perfect Score Module 2011 17

    7. Table 7.1 shows the electron arrangement for atoms W, X and Y. These letters are not the actual symbols of the elements.

    Table 7.1(a) State the position of element X in the Periodic Table of Elements.

    Explain how you determine the group and the period of element X.

    [4 marks](b) Atoms W and Y can form chemical bonds with atom X.

    Explain how the bond is formed between :

    (i) Atoms Y and X(ii) Atoms W and X

    [10 marks]

    (c) Table 7.2 shows physical property of compound P and compound Q.

    Table 7.2State the type of bond in compound P and compound Q.By choosing one physical property, explain why there is a difference between the propertyof the compounds.

    [6 marks]

    PAPER 2 SECTION C: ESSAY8 (a) Diagram 8 shows the apparatus set up to determine the empirical formula of oxide of metal M. M

    is less reactive than hydrogen.

    Diagram 8 (i) Name a suitable dilute acid and metal N that are used to prepare hydrogen gas.

    [2 marks](iii) Suggest a suitable chemical substance for R and state the function of R.

    [2 marks] (iv) State the example of oxide of metal M. Describe the redoxs reaction that occurs in the combustion

    tube based on the changes in oxidation number.[6 marks]

    Element Electron arrangement W 2.4

    X 2.8.7

    Y 2.8.8.1

    Physical Property Compound P Compound Q

    Melting point High Low

    Electrical conductivity Can conduct electricity in molten state or aqueous solution

    Cannot conductelectricity in molten andsolid states

    Dilute acid

    Thistle funnel

    R

    Heat

    Oxide of metal M

    Dry hydrogen gas

    Metal N

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    Chemistry Perfect Score Module 2011 18

    (b) The information below is about hydrocarbon Y

    Empirical formula of Y is CH 2 Molar mass of Y = 56 gmol -1

    (i) Determine the molecular formula for hydrocarbon Y.[Relative atomic mass of C =12 , H = 1 ]

    [2 marks]

    (ii) Describe an experiment to prepare hydrocarbon Y in the laboratory from its correspondingalcohol.In your answer, include the diagram of the appratus set-up, materials used, andprocedure.

    [8 marks]9 (a) (i) What is meant by empirical formula?

    [1 mark]

    (ii) Diagram 9.1 shows the apparatus set-up used to determine the empirical formula of oxideof metal X.

    Diagram 9.1

    Suggest one suitable oxide of metal X.Write a balanced chemical equation involved.

    [3 marks]

    (b) Diagram 9.2 shows the apparatus set-up used to determine the empirical formula of another oxide of metal.

    (h) Suggest one suitable oxide of the metal.[1 mark]

    (ii) Based one diagram 9.2, describe how you could determine the empirical formula of the named metal oxidein the laboratory. Your description should include

    - procedure of experiment- tabulation of results- calculation of the empirical formula

    [10 marks]

    (c) A carbon compound contains 84.6% of carbon and 15.4% of hydrogen by mass.The relative molecular mass of this compound is 70. Calculate the molecular formula of this compound.

    [Relative atomic mass: C, 12; H, 1] [5 marks]

    Heat

    Oxide of metal X

    Dry hydrogen gas

    Diagram 9.2

    Heat

    Metal

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    Chemistry Perfect Score Module 2011 19

    CHEMISTRY PERFECT SCORE MODULE

    SET

    1. Electrochemistry2. Oxidation and Reduction

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    Chemistry Perfect Score Module 2011 20

    PAPER 2: SECTION A [STRUCTURE]

    1 Diagram 1 shows the apparatus set- up for the combination of electrolytic cell and chemical cell.

    Diagram 1(a) Which cell is the electrolytic cell?

    ..... [1 mark]

    (b) Based on Cell I

    (i) State the negatif terminal of the cell .

    ..... [1 mark]

    (ii) Draw the flow of electron in Diagram 1.

    [1 mark](iii) State the observation at copper electrode.

    [1 mark]

    (c) Write half equation for the reaction at copper electrode .

    ...... [2 marks]

    (d) Based on the Cell II(i) State the energy change in the cell.

    . [1 mark]

    (ii) What can be observe at the copper(II) sulphate solution?

    . [1 mark]

    (iii) Explain your answer in d(ii)

    ..... [2 marks]

    Copper(II) sulphatesolution

    Cell IICell I

    V

    Magnesiumelectrode

    Copper electrode

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    2 (a) Diagram 2.1 shows the apparatus set-up to investigate the transfer of electrons at a distancebetween potassium iodide solution and acidified potassium manganate(VII) solution.

    Diagram 2.1

    (i) Name the product formed at electrode R.

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

    (ii) Complete the half equation for the reaction at electrode S.

    MnO 4- + ........ H + + ....... e Mn 2+ + ............... H 2O

    [1 mark](iii) State the change in oxidation number of manganese and name the process that occurs at S.

    Change in oxidation number : ........................

    Name of process : .................................................................................................................[2 marks]

    (iv) Suggest a substance that can replace potassium iodide solution in order to obtain the samereaction.

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

    (b) Diagram 2.2 shows the set up of the apparatus to investigate the reactivity of metals J, K and L.The different metals are heated consecutively.

    Diagram 2.2

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    Table 2.2 shows the observation of the experiment.

    Metal Observations Colour of residue

    Hot Cold

    J Burns brightly Yellow White

    K Glows dimly Black Black

    L Burns with a very bright flame White White

    Table 2.2(i) State the name of metal J.

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

    (ii) Write a chemical equation for the reaction between metal J and oxygen.

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

    (iii) Based on the observation in Table 2.1, arrange metals J, K and L in ascending order of

    reactivity towards oxygen.

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

    (iv) A mixture of metal J and oxide of metal L is heated strongly.Predict an observation. Give a reason.

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

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

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    PAPER 2: SECTION B [ESSAY]

    3 (a) Table 3.1 shows the electrical conductivity of two different compounds

    Compound Electrical conductivityPropanone (C 3H6O) Cannot conduct electricitySodium chloride solution (NaCl) Conduct electricity

    Table 3.1

    Referring to Table 3.1, explain why there is a difference in the electrical conductivity.[4 marks]

    (b) Diagram 3.1 shows two types of cells.

    Diagram 3.1Compare and contrast cell X and cell Y. Include in your answer the observations and half equations for the reactions at the electrodes in both cells.

    [8 marks](c) An experiment is carried out to determine the position of metals silver, L and M in the

    electrochemical series. Diagram 3.2 shows the results of the experiment.

    Experimen

    I II III

    Observation Grey solid deposited Colourless solution

    Grey solid deposited Light blue solution

    No change

    Diagram 3.2

    Copper plate

    Copper(II) sulphatesolution

    Zinc plateA B

    V

    C D

    Cell X Cell Y

    L

    Silver nitratesolution

    M

    Silver nitratesolution

    M

    L nitratesolution

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    (i) Based on the results in Diagram 3.2, arrange the electroposivity of metals silver, L and M in ascendingorder.Explain your answer.

    [7 marks](ii) Based on observation in experimen II, suggest one possible metal for M

    [1 mark]

    4 (a) The following is the chemical equation of a redoxs reactionZn + Pb(NO 3)2 Zn(NO 3)2 + Pb

    Referring to the above chemical equation,

    (i) Write half equation for the oxidation and the reduction reactions . [4 marks]

    (ii) Identify substance that is oxidized and reduced. Explain your answer in term of transfer of electrons.

    [4 marks]

    (b) Diagram 4 shows two redox reactions that take place in test tubes P and Q.

    (i) State the observations and write the ionic equation for the reaction in test tubes P and Qrespectively.

    [6 marks]

    (ii) State the name of the product formed in each test tube P and Q

    [4 marks](iii) Describe a confirmation test to verify the product in test tube Q[2 marks]

    Diagram 4

    Iron (II) sulphate

    Chlorine water

    Test tube P

    Potassium iodide

    Test tube Q

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    PAPER 2: SECTION C [ESSAY]

    5 (a) Diagram 5 shows the apparatus set-up and observations for experiments 1 using 1.0 moldm -3 aqueous solution of compound XSO 4 and experiment II using 0.0001 moldm

    -3 aqueous solution of compound XY 2.

    Experiment Apparatus set-up Observation

    I

    Cathode:Brown solid deposited

    Anode:A colorless gas is produced.

    II

    Cathode:Brown solid deposited

    Anode:A colorless gas is produced.The gas relight a glowing splinter.

    Diagram 5

    (i) In both experiment I and experiment II, the product formed at cathode is the same. Usingyour knowledge of factors affecting the selective discharge of ions at the electrodes,

    - suggest one possible cation for X 2+ ion- write the half equation for the reaction at the cathode- state the name of the product at cathode

    [4 marks]

    (ii) Name the product formed at anode in experiment I. Describe a confirmatory test to identify the

    gas produced. [3 marks]

    (iii) Suggest one possible anion for Y - ion in experiment II.Name the product at the anode and explain the formation of the product in the experiment.

    [6 marks](b) Pure copper metal is used to make copper wire.

    Describe how to purify the copper metal using an electrolysis process.Include a labelled diagram in your answer.

    [7 marks]

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    6 (a) Diagram 6.1 shows the apparatus set-up to study the effect of metals P and Q on the rusting of ironnail. The results are recorded after three days.

    Experiment Observation after 3 days

    I

    Dark blue precipitate Iron nail rust

    II

    Solution turns pink. Iron nail does not rust

    Diagram 6.1

    (i) Name one possible metal for metal P and metal Q[2 marks]

    (ii) Explain why there is a difference in observation in Experiment I and II.[8 marks]

    (b) Diagram 6.2 shows a redox reaction between bromine water and iron(II) sulphate solution.

    (i) Describe the redox reaction that occur in the test tube. Your answer should include the ionicequation and observations.

    [8 marks]

    (ii) Based on the oxidation reaction in (b) (i), describe a chemical test to identify the product formedin the test tube.

    [2 marks]

    Agar-agar solution with potassiumhexacyanoferrate(III) andphenolphthalein solution.

    Iron nail wrapped with metal P

    Agar-agar solution with potassiumhexacyanoferrate(III) andphenolphthalein solution.

    Iron nail wrapped with metal Q

    Diagram 6.2

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    Chemistry Perfect Score Module 2011 27

    CHEMISTRY PERFECT SCORE MODULE

    SET

    1. Acids and Bases2. Salts

    3. Rate of reaction4. Thermochemistry

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    PAPER 2 SECTION A [STRUCTURE]

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

    pH paper

    A B C D5 cm 3 HCl 5 cm 3 HCl 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?

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

    (b) If the hydrochloric acid in test tube B is replaced with 5 cm 3 of 0 .1 mol dm -3 ethanoic acid,

    predict the pH value of the solution. Explain your answer

    .....

    .

    . [3 marks]

    (c) Excess of magnesium powder is added to 5 cm 3 of 0.1moldm -3 hydrochloric acid in test tube A(i) Name the products formed.

    ......

    [1 mark](ii) Write an ionic 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 dm 3 at room conditions]

    [3 marks]

    Diagram 1

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    Add water

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

    .. [1 mark]

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

    (i) Give one example of each 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 decrease when water is added intobeaker J.

    7.04.8

    Glacial ethanoic acid+ solvent P

    Glacial ethanoic acid +solvent Q

    Beaker J

    100 cm 3 of 0.5 moldm -3 hydrochloric acid

    250 cm 3 of 0.04 moldm -3 hydrochloric acid

    Beaker L

    Diagram 2.1

    Diagram 2.2

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    (i) When water is added into beaker J, what happen to the pH value of the hydrochloric acid?Give reason to your answer.

    .

    . [2 marks]

    (ii) Calculate the volume of hydrochloric acid in beaker J that is needed to preparehydrochloric acid in beaker L.

    [2 marks]3. A student carried out an experiment to investigate the properties of three solutions. Table 3 shows the results

    of the experiments.

    Test tube P Q RSet-up of apparatus

    Observation The red litmuspaper turned blue.

    Table 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? Explain why.

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

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

    Ammonia gasdissolved inwater

    Red litmusPaper

    Ammonia gasdissolved inpropanone

    Red litmusPaper

    Hydrogenchloride gasdissolved in water

    Magnesium

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    (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 mark]

    (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 dm 3 at room conditions]

    [ 2 marks]

    4. Diagram 4 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) Name the reaction.

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

    b) Heating of copper(II) carbonate produces copper(II) oxide and gas R.i) Name gas R.

    .. [1 mark]

    ii) Write the chemical equation of the reaction.

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

    Copper(II)carbonate

    Copper(II) oxideSodium carbonateCopper(II)nitrate

    Copper(II) sulphate

    Diagram 4

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

    [2 marks]c) Copper(II) carbonate reacts with hydrochloric acid to produce copper(II) chloride. The chemical

    equation is shown below.CuCO 3 + 2HCl CuCl 2 + CO 2 + H 2O

    12.4 g copper(II) carbonate reacts completely with excess hydrochloric acid.Calculate the mass of copper(II) chloride.[Relative atomic mass: Cu = 64, C = 12, O=16 , Cl = 35.5, H=1)

    [2 marks]

    5. Three experiments were conducted to investigate the factors affecting the rate of reaction. The results areshown in the Table 5

    Experiment Reactants Temperature / 0C Time taken for all themagnesium to dissolve/s

    I0.4g 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

    III0.4g magnesium ribbon and 50 cm 3 1 moldm -3 hydrochloric acid and copper(II)sulphate solution

    30 45

    Table 5(a) Write a chemical equation to show the reaction between magnesium and hydrochloric acid.

    ..[2 marks]

    (b) Calculate the number of mole of [Relative atomic mass of Mg = 24](i) Magnesium

    [1 mark](ii) Hydrochloric acid

    [1 mark]

    (c) If hydrochloric acid used is excess, calculate the maximum volume of hydrogen gas produce atroom temperature and pressure.[1 mole of gas occupies the volume of 24 dm 3 at room temperature and pressure]

    [2 marks]

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    (d) Calculate the average rate of reaction for Experiment I and II.

    [2 marks](e) 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]

    6. An experiment is carried out to determine the heat of displacement for the reaction between copper(II)sulphate solution and excess zinc powder. 50.0 cm 3 of 0.5 mol dm 3 copper(II) sulphate solution is poured intoa plastic cup. The initial temperature of the solution is recorded after 5 minutes. 5 g of excess zinc powder isadded into a plastic cup. The mixture is stirred and the highest temperature is recorded.

    The following data is obtained:

    Initial temperature of copper(II) sulphate solution = 28.0 0CHighest temperature of the mixture reached = 38.0 0C

    [Relative atomic mass : Cu,64; S,32; O,16; Zn, 65; Specific heat capacity of water : 4.2 Jg 1 0C 1]

    (a) Based on the experiment, what is meant by the heat of displacement?

    ..... [1 mark]

    (b) Write an ionic equation for the reaction.

    .. [1 mark]

    (c) State two observations in the experiment.

    (i) ....

    (ii) .. ....[2 marks]

    (d) Calculate,(i) the heat released

    [1 mark](ii) the number of moles of copper (II) sulphate reacted

    [1 mark]

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    (iii) the heat of displacement

    [2 marks](e) Why excess zinc powder is used in this experiment?

    ......

    [1 mark](f) Draw the energy level diagram for the reaction.

    [2 mark]7. 50 cm 3 1.0 mol dm -3 sodium hydroxide solution is poured into a polystyrene cup. The polystyrene cup is

    then placed into a beaker as shown in Diagram 5

    Diagram 5

    The initial temperature of sodium hydroxide solution in the polystyrene cup is measured. 10 cm 3 of hydrochloric acid is added to the 50 cm 3 sodium hydroxide and the temperature increase is recorded. Then,the heat energy released is calculated. The experiment is repeated by adding different volumes of hydrochloric to the 50 cm 3 of sodium hydroxide. The results are tabulated as shown below.

    Volume of sodium hydroxidesolution / cm 3

    Volume of hydrochloric acidadded / cm 3

    Heat energy released / kJ

    50 10 1.150 20 2.250 30 3.450 40 4.550 50 5.650 60 5.650 70 5.6

    (a) Plot a graph heat energy released against volume of hydrochloric acid added.[3 marks]

    (b) (i) Based on the graph, determine the volume of hydrochloric required for completeneutralisation with 50 cm 3 1.0 mol dm -3 sodium hydroxide

    [1 mark]

    (ii) From your answer in (b) (i), calculate the concentration of hydrochloric acid usedin moldm -3.

    [2 marks]

    Polystyrene cupBeaker

    Sodium hydroxide solution +hydrochloric acid

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    (c) Why the content in the polystyrene cup has to be stirred continuously throughout theexperiment?

    .. [1 mark]

    (d) Explain briefly why the heat released becomes constant after 50 cm 3 of hydrochloric acid isadded.

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

    (e) (i) Calculate the heat energy released when 1 mole of sodium hydroxide is neutralizedby hydrochloric acid.

    [1 mark]

    (ii) Draw the energy level diagram for the reaction that occurred in the polystyrene cup.

    [2 marks](f) In another experiment, 50 cm 3 1.0 mol dm -3 sodium hydroxide solution is added with 50 cm 3 1.0

    mol dm -3 ethanoic acid.

    (i) Predict the heat energy released

    . [1 mark]

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

    [2 marks]

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    PAPER 2: SECTION B [ ESSAY]

    8. 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 labelled 1 to 7. A fixed volume of 5.0 cm 3 of 1.0 mol dm -3 potassium iodide solution was placed in each test tube. 0.5 cm 3 of 1.0 moldm -3 lead(II) nitrate solution wasadded into test tube 1, 1.0 cm 3 into test tube 2 and so on until 3.5 cm 3 was added into test tube 7. Theheights of the precipitate formed in each test tube were measured.

    The results are shown in Table 6.

    Test tube1 2 3 4 5 6 7

    Volume of 1.0 moldm -3 lead(II)nitrate solution/ cm 3 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 8

    (a) Based on Table 8,

    (i) Plot a graph of the height of the precipitate against volume of lead(II) nitrate solution on thegraph paper provided .

    [3 marks]

    (ii) Determine the volume of lead(II)nitrate solution that had reacted completely with 5.0 cm 3 of 1.0 moldm -3 potassium iodide.

    [1 mark]

    (iii) Using the volume obtained in (a) (ii), calculate the number of moles of lead(II) ions and iodideions that are required for the formation of lead(II) iodide.Then, calculate the number of moles of iodide ions that has reacted with 1 mol of lead(II) ions.

    [4 marks]

    (iv) Write the ionic equation for the formation of lead(II) iodide.[2 marks]

    (b) By referring to test tube 1, 5 and 7 in Table 8, state the ions that exist in the solution. Explain youranswer.

    [10 marks]

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    9. (a) (i) The rate of reaction is important in industries and in our everyday lives.

    State the four factors that affect the rate of reaction. [4 marks]

    (i) What are the conditions required for the production of ammonia in Haber Process? [3 marks]

    (b) A student carried out two experiments to investigate the effect of concentration on the rate of reaction.Diagram 9.1 shows the set-up of apparatus of the experiments.

    Experiment Set-up of apparatus

    I

    Diagram 9.1

    Table 9.2 shows the result of the experiments.Time /s 0 30 60 90 120 150 180 210

    Volume of gas of Experiment I / cm 3 0.00 5.00 10.00 14.20 18.00 21.30 24.00 26.00

    Volume of gas of Experiment II / cm 30.00 10.00 17.00 23.00 25.00 26.00 26.00 26.00

    Table 9.2

    (i) Plot the graph of the volume of carbon dioxide gas against time for Experiment I and II on thesame axes on the graph paper provided .

    [4 marks](ii) Calculate the average rate of reaction for Experiment I and II .

    [4 marks](iii) Compare the rate of reaction between Experiment I and Experiment II .

    Explain the differences in the rate of reaction with reference to the collision theory.[5 marks]

    0.2 g calcium carbonate powder

    Excess hydrochloric acid0.2 mol dm -3

    Water

    Air

    0.2 g calcium carbonate powder

    Excess hydrochloric acid0.5 mol dm -3

    Water Air

    II

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    Question 9 (b) (i)

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    PAPER 2: SECTION C [ESSAY]

    10. Table 10 shows the data from Experiment I and Experiment II that were carried out to study the rate of reaction of magnesium ribbon with two acids, X and Y .

    Experiment Reactants Products

    I Excess of magnesium ribbon and 50 cm 3 of acid X 1.0 mol dm -3

    Magnesium chloride and hydrogen gas

    II Excess of magnesium ribbon and50 cm 3 of acid Y 1.0 mol dm -3 Magnesium sulphate and hydrogen gas

    Table 10

    (a) (i) State the name of the acid X and Y.Write the chemical equation for the reaction of this acid with magnesium.

    [3 marks]

    (ii) Calculate the number of mol of acid X or acid Y that react with excess magnesium ribbon.[1 mark]

    (iii) Based on this experiment what is meant by the rate of reaction?[1 mark]

    (b) (i) At the same axis, sketch the graph of volume of gas against time for experiment I andexperiment II.

    [ 2 marks] (ii) Compare the rate of reaction in experiment I and II . Explain your answer based on collision

    theory.[5marks]

    (c) Describe one laboratory experiment to conduct the Experiment I or Experiment II to determine the

    rate of reaction. Your answer should include the following :- A labeled diagram showing the apparatus set-up- Procedures of the experiment- A table to collect the data

    [8 marks]11. a) A student with a wet T-shirt entered an air-conditioned room. After half an hour, the student was

    shivering with coldness. Explain this pheomena with reference to changes in physical state andenergy change involved.

    [2 marks]b) Table below shows the molecular formula and heat of combustion for ethanol and propanol.

    Alcohols Molecular Formula Heat of Combustion, HEthanol C 2H5OH - 1,376 kJ / molPropanol C 3H7OH - 2,015 kJ / mol

    Based on the information above,(i) Write the thermochemical equation for the combustion of ethanol.

    [2 marks](ii) Compare the heat of combustion between ethanol and propanol. Explain your answer.

    [4 marks](iii) Describe an experiment to determine the heat of combustion of ethanol. Include the

    following in your answer : Set-up of apparatus

    Materials and apparatus Procedure Results and calculation

    [12 marks]

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    12. (a) What is meant by exothermic and endothermic reaction?Explain the changes in energy content of the reactants and products for both of the reactions.

    [4 marks]

    (b) Diagram represent the energy level diagram for a chemical reaction

    State four information that can be obtained from the above diagram.[4 marks]

    (c) Reaction I and II below are the thermochemical equation for the heat of precipitation.Reaction I : AgNO 3 + NaCl AgCl + NaNO 3 H = - 210 kJmol

    -1

    Reaction II : AgNO 3 + KCl AgCl + K NO 3 H = - 210 kJmol -1

    Explain why the value of heat of precipitation in reactions I and II are the same.

    [4 marks]

    (d)

    Describe a laboratory experiment to determine the heat of reaction for the above reaction. In youranswer, include the following :

    chemicals required procedures of the experiment results and calculation involved

    [8 marks]

    Energy

    A + B

    C + D

    H = + x kJ / mol

    Ca2+(aq) + CO 32- (aq) CaCO 3 (s) H = + 12.6 kJmol

    -1

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    13. Diagram 13.1 shows the flow chart for the preparation of magnesium carbonate and magnesium sulphatethrough reaction I and II.

    Diagram 13.1

    a) (i) Based on the Diagram 13.1 , classify the above salts to soluble salt and insoluble salts.[2 marks]

    (ii) State the reactant used for the preparation of magnesium carbonate from magnesium nitrate inreaction I and II

    [2 marks](iv) Describe the preparation magnesium carbonate from magnesium nitrate in the laboratory through

    reaction I[6 marks]

    b) Diagram 13.2 shows conversion of salt X when it heated strongly and dissolved in water. The solutionformed is tested with sodium hydroxide solution, NaOH.

    + +

    Diagram 13.2

    Based on the information in the Diagram 13.2,

    (i) Identify an anion that is present in salt X. Describe a chemical test to verify the anion.

    [4 marks](ii) Identify three cations that are possible present in salt X solution.

    Describe chemical test to verify the cations.[6 marks]

    Salt X solid Metal oxide Brown gas Colourless gas

    Salt X solution A white precipitate soluble in excess NaOH.NaOH solution

    H2O

    Magnesium nitrate Magnesium carbonate Magnesium sulphateReaction I Reaction II

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    Chemistry Perfect Score Module 2011 43

    CHEMISTRY PERFECT SCORE MODULE

    SET

    1. Carbon Compounds2. Manufactured Substances in Industry3. Chemicals for Consumers

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    PAPER 2: SECTION A [STRUCTURE]

    1. Diagram 1 shows the structural formula of compound X.

    Diagram 1

    (a) Compound X is an unsaturated hydrocarbon.What is the meaning of unsaturated hydrocarbon?

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

    (b) State the homologous series for compound X.

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

    (c) Name the compound X.

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

    (d) At 180 oC and in the presence of nickel as catalyst, compound X can be changed into saturatedhydrocarbon compound.

    (i) Name the reaction.

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

    (ii) Draw the structural formula for the compound formed.

    [1 mark](e) Compound X burns completely in excess oxygen.

    (i) Write a balanced chemical equation for the complete combustion of X.

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

    (ii) 2.1 g of compound X undergoes complete combustion at room conditions.Calculate the volume of carbon dioxide gas released.

    [1 mol of gas occupies 24 dm 3 at room conditions; Relative atomic mass: H = 1; C = 12]

    [2 marks]

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    2. Diagram 2 shows a series of reactions.Compound P with the molecular formula C 2H6O, can be prepared through fermentation of glucosesolution.

    Diagram 2(a) Name the compound P.

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

    (b) State the functional group of compound P.

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

    (c) In the reaction I, compound Q is produced when an acidified potassium dichromate (VI) solution isadded into a test tube containing compound P.(i) Name the reaction I.

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

    (ii) State one observation for this reaction.

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

    (iii) Draw the structural formula of compound Q.

    [1 mark](d) In the reaction II, compound R is formed when compound P reacts with compound Q in the

    presence of concentrated sulphuric acid.

    (i) Name the reaction II.

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

    (ii) Name the compound R.

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

    (iii) Give one special physical property of compound R.

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

    (iv) Write the chemical equation for the reaction II.

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

    Glucose

    Compound PC2H6O

    Compound Q

    Compound R

    Reaction II

    Reaction I

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    3. (a) Diagram 3.1 shows the manufactured of ammonia and sulphuric acid.

    Diagram 3.1

    Based on Diagram 3.1, answer the following questions.(i) State the name of Process I.

    . [1 mark]

    (ii) Write the chemical equation for the reaction to produce ammonia in Process I.

    .. ...

    [2 marks](iii) In Process II, sulphur dioxide is reacted with oxygen to produce sulphur dioxide.

    State the temperature and the catalyst used in this reaction.

    .

    . [2 marks]

    (iv) State one use of ammonium sulphate.

    . [1 mark]

    (b) Diagram 3.2 shows a structural formula of a polymer.

    Diagram 3.2

    (i) State the name of the polymer in Diagram 3.2

    [1 mark](ii) Draw the structural formula for the monomer in Diagram 3.2

    [1 mark]

    (c) Bronze is an alloy of copper. Draw a labeled diagram to show the arrangement of atoms in bronze.

    [2 marks]

    Process I Ammonia

    Process II Sulphuric acid

    Ammonium sulphate

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    4. The following equation shows how soap can be prepared.

    palm oil + potassium hydroxide substance Z + soap

    (a) (i) State the name of substance Z .

    [1 mark]

    (ii) State the name of the process in the above reaction.

    [1 mark]

    (iii) Explain why potassium chloride is added during the preparation of soap.

    [1 mark]

    (b) Two cleaning agents, X and Y, are used to wash clothes in river water and sea water. The results obtainedare shown in Table 4 below.

    Cleaning agent River water Sea water X Does not form scum Does not form scumY Does not form scum Forms scum

    Table 4

    (i) State the type of cleaning agents X and Y.

    X : ..

    Y : [2 marks]

    (ii) State the name of the scum formed if Y is sodium stearate.

    [1 mark]

    (iii) State the two ions present in sea water that cause the formation of scum in Y.

    [2 marks]

    (iv) Give one disadvantage of using the cleaning agent X.

    [1 mark]

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    PAPER 2: SECTION B [ESSAY]

    5. (a) A hydrocarbon M, consists of 85.7% of carbon and X% of hydrogen by mass. The relativemolecular mass of M is 56.[Relative atomic mass: C = 12; H = 1]

    (i) What is the value of X.[1 mark]

    (ii) Determine the empirical formula and molecular formula of hydrocarbon X.

    [5 marks](iii) Draw the structural of the two isomers of hydrocarbon M.

    Write the names for each isomer[4 marks]

    (iv) Compound M burns with sootier flames as compared to butane.Explain and prove.

    [3 marks](b) Natural rubber is a natural polymer.

    (i) Give another two examples of natural polymer.[2 marks]

    (ii) Name and draw the structural formula of the monomer of natural rubber.[2 marks]

    (c) The tyres of aircrafts are made from vulcanised rubber.(i) What is vulcanised rubber?

    [1 marks](ii) Explain why vulcanised rubber is more elastic than unvulcanised rubber.

    [2 marks]

    6. (a) Food preservatives are substances added to food so that the food can be kept for longer periodsfor time. Using two suitable examples, explain how they work as preservative.

    [4 marks](b) The following is the information about a child.

    2 years old

    High fever Whooping cough

    Based on the information above,(i) Name two examples of modern medicine that can be used to treat the child .

    [2 marks](ii) State two precautions that should be taken by the parents while giving the medicine to

    their child.[2 marks]

    (iii) Explain the effect if the precautions states in (b)(ii) are not followed properly.[2 marks]

    (c ) Table 6 shows the food additives that are added to a certain food by two chefs.

    Chef Wan Chef KohTurmericSugar, salt and spiceGarlic

    TartrazineMonosodium glutamateAscorbic acid

    Table 6

    Based on Table 6, categorise the food additives. Include in your answer the function of eachtype of food additives and the disadvantages of using any two food additives.

    [10 marks]

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    PAPER 2: SECTION C [ESSAY]

    7. Diagram 7 shows the flow chart for the industrial manufacture of sulphuric acid and the production of three types of fertilizer.

    Diagram 7

    (a) (i) Based on step I to step IV , describe briefly the industrial production of sulphuric acid.[4 marks]

    (ii) Write a chemical equation for the reaction between sulphuric acid and ammonia toproduce fertilizer Y.

    [2 marks](b) Table 7 shows the diameter of the dent formed in an experiment to compare the hardness of

    copper and bronze. Based on Table 7, compare the hardness between copper and bronze, explainwhy ?

    Material Diameter /cmCopper 1.0Bronze 0.5

    Table 7

    [4 marks]

    (c) The iron window frame of Encik Azmans house rusts after several years but the steel windowframe of Encik Tarmizis house does not rust. By using suitable examples, describe a laboratory experiment to compare the resistant to rust of alloy compared to pure metal.Include the following in your answer:

    Procedure Results Conclusion

    [10 marks]

    8. (a) Table 8 shows the result of two sets of experiment to investigate the coagulation of latex.

    Set Type of solution Observation

    I Latex + solution X Latex coagulate very fastII Latex + solution Y Latex does not coagulate

    Table 8

    (i) Suggest one possible substance for solution X. and Y[2 marks ]

    (ii) Explain the process of coagulation of latex in set I

    [4 marks ](iii) Explain why latex does not coagulate in set II

    [2 marks ]

    Sulphur Sulphur dioxide Substance X

    OleumSulphuric acid

    + Ammonia

    Fertiliser Y

    Step 1 Step II

    Step III

    Step IV

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    (b) Diagram 8 shows how compound Q is formed from alkene W.

    Diagram 8

    (i) Name the homologous series of compound Q.

    [1 mark](ii) State two chemical properties of compound Q.

    [2 marks]

    (iii) By using a compound Q with number of carbon atom per molecule more than one,describe an experiment to convert compound Q to alkene.Your answer should consist of the following:

    Procedure of the experiment A labelled diagram showing the apparatus set-up The test to confirm the product is alkene

    [9 marks]

    Alkene W + H 2O Compound Q

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    CHEMISTRY PERFECT SCORE MODULE

    SET

    1. PAPER 3 SET 1

    2. PAPER 3 SET 2

    3. PAPER 3 SET 3

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    PAPER 3 SET 11. Diagram 1.1 shows the set-up of apparatus for an experiment to compare the hardness of a metal and its

    alloy.

    A steel ball bearing is taped onto the material X block using cellophane tape. A weight of 1 kilogram isdropped at a height of 50 cm to hit the ball bearing. The diameter of the dent made on the material Xblock is measured. The experiment is repeated by replacing material X block with material Y block.Table 1.1 shows the view of the dents made on the material X and Y.

    Experiment Material X Material YI

    II

    III

    Diameter: ................. Diameter: .................

    Diameter: ................. Diameter: .................

    Diameter: ................. Diameter: .................

    Table 1.1

    Diagram 1.1

    Material X

    Retort stand

    Thread

    Weight

    Meter ruler

    Steel ballbearing

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    (a) (i) Using a ruler, measure the diameters of the dents made on material X and Y. Record all thediameters of the dents in table 1.1.

    [3 marks](ii) Construct a table to record the diameters of the dents and average diameter on material X and

    material Y.

    [3 marks](b) State one observation that can be obtained from this experiment.

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

    .. [3 marks]

    (c) Based on the average diameter of the dents on material X and Y, state the inference that can be make.......................................................................................................................................................................

    .. [3 marks]

    (d) State the operational definition for the hardness of alloy.......................................................................................................................................................................

    .. [3 marks]

    (e) Explain why there is difference in diameter of dents on material X and Y.

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

    .. [3 marks]

    (f) Suggest a suitable material for X and Y.

    ......................................................................................................................................................................[3 marks]

    (g) State the hypothesis for this experiment.......................................................................................................................................................................

    .. [3 marks]

    (h) Complete table 1.2 based on the experiment.

    Name of variables Action to be taken(i) Manipulated variable: (i)The way to manipulate variable:

    (ii) Responding variable: (ii) What to observe in the responding variable:

    (iii) Controlled variable: (iii) The way to maintain the control variable:

    [3 marks]Table 1.2

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    2. Diagram 2 shows the set-up of apparatus to investigate the effect of other metals X, Y and Z on therusting of iron. A mixture of jelly solution, potassium hexacyanoferrate(III) solution andphenolphthalein were used as medium in each test tube. The observations were recorded after one day.

    Test tube AIron nail coiled with metal X

    Test tube BIron nail coiled with metal Y

    Test tube CIron nail coiled with metal Z

    Test tube DIron nail

    (a) State the inference for the observation in test tube A, B, C and D.

    Test tube Inference

    A

    B

    C

    D

    [3 marks](b) Based on this experiment, explain why there is a difference in the observation between test tube A

    and B.

    [3 marks]

    Diagram 2

    Low intensity of blue colour

    Low intensity of pink colour

    High intensity of pink colour

    High intensityof blue colour.

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    (c) State the hypothesis for the experiment.

    [3 marks]

    (d) Based on this experiment state:

    (i) The manipulated variable: ...

    (ii) The responding variables :.

    (iii) The constant variables :.... [3 marks]

    (e) State the operational definition for the rusting of iron nail.

    [3 marks]

    (f) Based on this experiment classify the metals that can provide sacrificial protection and metal cannotprovide sacrificial protection to iron.

    [ 3 marks](g) Observation in test tube D is recorded after two days. Compare the observation for the experiment

    after it left for one day and two days. Explain your answer.

    After one day

    After two days

    .

    [3 marks]

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    ESAY / PLANNING

    3. Different type of alcohols produces different heat of combustions. When the number of carbon permolecule of alcohol increases the heat of combustion increases. Table 3.1 shows the heat of combustionof ethanol, propanol and butanol.

    Alcohol Molecular formula Heat of combustion/ kJ mol -1

    Ethanol C 2H5OH -1376Propanol C 3H7OH -2016

    Butanol C 4H9OH -2678

    Plan a laboratory experiment to compare the heat of combustion of the alcohols. Your planning mustinclude the following aspects:(a) Statement of the problem(b) All the variables(c) Hypothesis(d) List of materials and apparatus(e) Procedure

    (f) Tabulation of data[17 marks]

    PAPER 3 SET 2

    1. A student carried out an experiment to determine the end-point for the titration of 25.0 cm 3 of 1.0 moldm -3 sodium hydroxide solution with hydrochloric acid. Phenolphthalein is used as the acid-baseindicator. Table 1 shows the three titrations that were conducted and the magnification of the burettereadings.

    TitrationNo.

    I II III

    Initial burettereading

    .. .. ..

    Final burettereading

    .. . ...

    Table 1

    Table 3.1

    hydrochloricacid

    27

    26

    hydrochloricacid

    39

    38

    hydrochloricacid

    14

    13

    hydrochloricacid

    27

    26hydrochloricacid

    2

    1 hydrochloricacid

    14

    13

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    (a) Record the burette readings for the three titrations in the spaces provided in Table 1.

    [3 marks]

    (b) Construct a table and record the initial burette reading, final burette reading and the volume of acid used for each titration.

    [3 marks](c) Calculate the molarity of the hydrochloric acid used in the experiment.

    [ 3 marks]

    (d) State the operational definition for the neutralization of sodium hydroxide solution in this experiment.

    ..

    . [3 marks]

    (e) The experiment is repeated by replacing hydrochloric acid 1.0 mol dm -3 with sulphuric acid 1.0 moldm -3.

    (i) Predict the volume of sulphuric acid needed to neutralise the sodium hydroxide solution.

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

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

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

    . ................................................................................................................................................[3 marks]

    (f) Table 1 shows the results of an experiment to investigate the pH values of acids.

    Solution pH value

    Hydrochloric acid, 1.0 mol dm-3

    2.0Ethanoic acid, 1.0 mol dm -3 5.0

    Table 1For this experiment, state(i) The manipulated variable

    .........................................................................................................................................................(ii) The responding variable

    .. ...............................................................................................................................................(iii) The fixed variable

    .. ...............................................................................................................................................[3 marks]

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    (g) State one hypothesis for this experiment.

    ..

    . [3 marks]

    (h) Classify the following substances into substances with pH value less than 7 and pH value more than 7.

    Ethanoic acid Barium hydroxideAmmonia solution Nitric acid

    [3 marks]2. Diagram 2.1 shows the apparatus set up for the preparation of ester in the laboratory.

    Table 2.1 show some examples of the types of alcohol and carboxylic acid used to prepare ester.

    Alcohol Carboxylic Acid ObservationMethanol Ethanoic acid Sweet pleasant smellEthanol Propanoic acid Sweet pleasant smellPropanol Methanoic acid Sweet pleasant smell

    Table 2.1

    (a) State one inference for this experiment.

    .

    [3 marks]

    heat

    water in

    water out

    Mixture of alchohol +carboxylic acid and a fewdrops of concentratedsulphuric acid

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    (b) Construct a table to show the alcohols and carboxylic acid from table 2.1 and the esters formed.

    [3 marks]

    (c) Propyl butanoate is an ester that is formed from the reaction between an alcohol and carboxylicacid.Name the alcohol and carboxylic acid needed to prepare the ester.

    Alcohol: .....................................................................................................................................Carboxylic acid: ........................................................................................................................

    [3 marks]

    (d) Table 2.2 shows the observation for an experiment to differentiate between alkanes and alkenes.Experiment Hexane Hexene

    Added with bromine water No change Brown bromine decolourisedAdded with acidified potassiummanganate (VII) solution

    No change Purple solution decolourised

    Table 2.2

    (i) State the variables for this experiment:

    Manipulated variable.:.....................................................................................................

    Responding variable..:....................................................................................................

    Fixed variable ........................................................................................................................[3 marks]

    (ii) State one hypothesis for this experiment..

    ...

    [3 marks](iii) Give the operational definition for alkene in this experiment.

    . ...

    [3 marks](iv) Hexene can also be differentiated from hexane with sootiness of flame when burnt.

    Predict which substance will produce more soot when burnt. Explain your answer.

    .

    ...

    . [3 marks]

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    3. Diagram 3 shows the set-up of apparatus used to investigate the cleansing action of a cleaning agent ona piece of cloth stained with oil.

    Experiment Apparatus Observation

    I Oil stained remains

    II Oil stained remains

    Based on the above diagram, plan one laboratory experiment to compare the effectiveness of cleaningagents A mad B on cleansing action in hard water.Your planning should include the following aspects:

    (a) Aim(b) All the variables(c) Statement of the hypothesis(d) List of substances and apparatus(e) Procedure of the experiment(f) Tabulation of data

    [17 marks]

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    SET 31. Diagram 1.1 shows the set-up of apparatus and thermometer reading for the experiment to

    compare the heat of combustion of four alcohols, methanol (CH 3OH), ethanol (C 2H5OH),propanol (C 3H7OH) and butanol (C 4H9OH). The initial and final mass of the spirit lampcontaining alcohol is weighed and recorded. The alcohols is used to heat 200 cm 3 of water .

    Diagram 1.1

    (a) Based on Diagram 1.1,

    (i) record the initial and highest reading of the thermometer in the spaces provided.[3 marks]

    (ii) State one observation

    .......................................................................................................................................................[3 marks]

    (ii) Give one inference based on the observation in (a)(ii).

    .......................................................................................................................................................[3 marks]

    Thermometer

    Water

    Initial temperature:.........................

    Methanol

    Copper tin

    Wind shield

    Highest temperature:...................

    Methanol

    Thermometer

    Co er tin

    Water

    Wind shield

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    (b) Diagram 1.2 shows the initial and final reading of the electronic balance for the mass of spiritlamp before burning and after burning of four alcohols.

    Alcohol Initial reading (g) Final reading (g) Mass of alcohol used (g)

    Methanol

    Ethanol

    Propanol

    Butanol

    Diagram 1.2Based on Diagram 1.2,(i) state the mass of the alcohols used in space provided into two decimal places.

    [ 3 marks]

    (ii) Tabulate the initial mass, final mass and mass of alcohol used for the four alcohols in thisexperiment.

    [3 marks]

    ONOFF 354.9548 g

    ONOFF 353.4012 g

    ONOFF 339.7892 g

    ONOFF 364.4303 g

    ONOFF 360.8702 g

    ONOFF 332.9891 g

    ONOFF 328.9790 g

    ONOFF342.0201 g

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    (c) Calculate the heat of combustion of methanol.[Specific heat capacity of water = 4.2 J g -1 oC -1]

    [3 marks](d) Table 1.1 shows the heat of combustion of ethanol (C 2H5OH), propanol (C 3H7OH) and butanol

    (C4H9OH).Alcohol Molecular Formulae Heat of combustion/kJ mol -

    Ethanol C 2H5OH 970Propanol C 3H7OH 1400Butanol C 4H9OH 1860

    Table 1.1For this experiment, state:(i) The manipulated variable.................................................................................

    The responding variable.....................................................................................

    The fixed variable...............................................................................................[3 marks]

    (ii) State one hypothesis for this experiment.

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

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

    .............................................................................................................................................................[3 marks]

    (e) If the experiment is repeated using pentanol, predict the heat of combustion of pentane.

    ............................................................................................................................................................[3 marks].

    (f) State the operational definition for the heat of combustion of methanol.

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

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

    ...........................................................................................................................................................[3 marks]

    (g) The actual heat of combustion for ethanol is 1376 kJ mol -1.State three reasons why the experimental value heat of combustion for ethanol is less than theactual value.

    1. ................................................................................................................................................

    2. ................................................................................................................................................

    3. ................................................................................................................................................[3 marks]

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    (h) Table 1.2 shows the list of carbon compounds and their molecular formula.Carbon compound Molecular formula

    Hexene C 6H12

    Propanoic acid C 2H5COOH

    Ethanol C 2H5OH

    Methane CH 4

    Classify the above carbon compounds into hydrocarbon and non hydrocarbon.

    [3 marks]2. Diagram 2.1 and 2.2 show Experiment I and Experiment II to investigate the effect of type of

    electrodes on the products formed at the electrodes.

    Experiment I

    Experiment II

    Based on Diagram 2.1 and Diagram 2.2 above, plan a laboratory experiment to investigate the effectof the type of electrode to the product at anode.Your answer should consist of the following:

    (a) Aim of experiment

    Diagram 2.1

    After 30 minutes

    Carbon Carbon

    After 30 minutes

    Copper electrodes

    0.01 mol dm