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Untuk Kegunaan Pemeriksa

Bahagian Soalan MarkahPenuh

MarkahDiperoleh

1 11

2 9

3 10

4 10

5 10

A

6 10

7 20B

8 20

9 20C

10 20

Jumlah

Nama : ……………………………………………... Kelas : …...……

SEKTOR SEKOLAH BERASRAMA PENUHKEMENTERIAN PELAJARAN MALAYSIA

_______________________________________________

PEPERIKSAAN AKHIR TAHUN TINGKATAN 4

2006

KIMIA

KERTAS 2

Dua jam Tiga Puluh Minit

JANGAN BUKA KERTAS SOALAN INI SEHINGGA DIBERITAHU

1. Tuliskan nama dan tingkatan padaruang yang disediakan.

2. Calon dikehendaki membacamaklumat di halaman 2.

Kertas soalan ini mengandungi 24 halaman bercetak

4541/2KimiaKertas 2Nov20062½ Jam

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INFORMATION FOR CANDIDATES

1. This question paper consists of three sections: Section A, Section B and Section C.

2. Answer all questions in Section A. Write your answers for Section A in the spacesprovided in the question paper.

3. Answer one question from Section B and one question from Section C.Write your answers for Section B and Sectioin C on the lined pages at the end of thequestion paper. Answer questions in Section B and Section C in detail. You may usequestions, diagrams, tables, graphs and other suitable methods to explain your answer.

4. Show your working. It may help you to get marks.

5. If you wish to cancel any answer, neatly cross out the answer.

6. The diagrams in the question are not drawn to scale unless stated.

7. Marks allocated for each question or part question are shown in brackets.

8. The time suggested to answer Section A is 90 minutes, Section B is 30 minutes andSection C is 30 minutes.

9. You may use a non-programmable scientific calculator.

10. Hand in this question paper at the end of the examination.

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Section A

[60 marks]

Answer all questions in this section.

The time suggested to complete Section A is 90 minutes.

1 Figure 1 shows part of the Periodic Table of the Elements. A, B, C, D, E, F, G and Hdo not represent the actual symbol of the elements.

A FB D E G

C H

FIGURE 1Using the letters in the Periodic Table of the Elements in Figure 1, answer thefollowing questions.

(a) Choose two elements which are metals and are placed in the same group.

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

(b) Write the electron arrangement for an atom of element F.

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

(c) Write the formula for the ion formed from an atom of element D.

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

(d) (i) State an element which has a special characteristic that is can form colouredcompound.

……………………………………………………………………………[1 mark]

(ii) State another special characteristic for the element that is stated in (d)(i).

……………………………………………………………………………[1 mark]

(e) State one element that forms acidic oxide.

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

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(f) Arrange A, B, D, E, F and G according to the increase in size of the atoms.

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

(g) Element A can react with water.(i) Write the chemical equation for the reaction between A and water.

………………………………………………………………………………[1 mark]

(ii) When a red litmus paper is put into the solution in (g)(i), the red litmus paperturns blue. Based on the observation, state the property of the solutionformed.

………………………………………………………………………………[1 mark]

(h) Element H is less reactive than element E. Explain why.

…………………………………………………………………………………...

…………………………………………………………………………………...

…………………………………………………………………………………...

…………………………………………………………………………………...

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

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2 Figure 2 shows the structural formula of compound X.

FIGURE 2

(a) What is the meaning of molecular formula?

…..…………………………………………………………………………….

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

(b) Write the molecular formula of compound X.

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

(c) Can compound X conduct electricity? State a reason for your answer.

………………………………………………………………………………….

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

C

C

C C

C

O

H

OH

CH2OH

H

H

H OH

OH

H

OH

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(d) Compound Y contains 52.2% of carbon, 13.0% of hydrogen and 34.8% ofoxygen by mass.Given that the relative atomic mass of H=1, C=12, O=16.

(i) Find the empirical formula of compound Y.

[3 marks]

(ii) If the molar mass of compound Y is 46 gmol-1, find its molecular formula.

[2 marks]

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3 (a) Figure 3 shows the flow chart for the industrial manufacture of sulphuric acid.

FIGURE 3

Based on Figure 3, answer the following questions.

(i) Name the process of manufacturing sulphuric acid.

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

(ii) Describe how sulphur dioxide gas can be produced at stage I .

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

(iii) Name catalyst X in stage II.

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

(iv) Write the chemical equation for the reaction that takes place at stage II.

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

(v) At stage III, sulphur trioxide is dissolved in concentrated sulphuric acid toproduce oleum. Write the chemical formula of oleum.

……………………………………………………………………………………[1 mark]

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(b) Brass is an example of alloy.

(i) Name the main element which is added to copper to form brass.

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

(ii) Draw the arrangement of atoms in pure copper and brass.

Pure copper Brass[2 marks]

(iii) Brass is harder than copper. Explain why.

…………………………………………………………………………………...

…………………………………………………………………………………...

…………………………………………………………………………………...

…………………………………………………………………………………...

…………………………………………………………………………………...

[2 marks ]

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4 An activity is carried out in the laboratory to determine the end point of the reactionbetween 25.0 cm3 of potassium hydroxide solution and 1.0 moldm-3 of sulphuric acid.Phenolphthalein is used in the titration to detect the end point of the reaction.Figure 4 shows the set-up of apparatus for the titration.

FIGURE 4

The volume of sulphuric acid added and the changeshydroxide solution are shown in the Table 4 below.

TABLE 4

(a) Name the chemical reaction between potassisulphuric acid.

………………………………………………

(b) Write a chemical equation for the reaction.

………………………………………………

Volumeofsulphuricacid(cm3)

4.50 4.60 4.70 4.80 4.90 5.00

Colour ofpotassiumhydroxidesolution

Pink Pink Pink Pink PinkColour-

less

Sulphuric acid1.0 moldm-3

25.0 cm3 of potassiumhydroxide solution and afew drops of

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of the colour of potassium

um hydroxide solution and

………………………………[1 mark]

……………………………...[1 mark]

5.10 5.20 5.30 5.40

Colour-less

Colour-less

Colour-less

Colour-less

phenolphthalein

White tile

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(c) Write the formula of ions which are present in the conical flask when thevolume of sulphuric acid added is:

(i) 4.50 cm3

………………………………………………………………………………(ii) 5.30 cm3

………………………………………………………………………………[2 marks]

(d) How much sulphuric acid is required to neutralise 25.0 cm3 of potassiumhydroxide solution?

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

(e) Calculate the molarity of potassium hydroxide used in the above activity.

[3 marks]

(f) If sulphuric acid is replaced with nitric acid with the same molarity, predictthe volume of nitric acid require to neutralise 25.0 cm3 of the potassiumhydroxide solution. Explain why.

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

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

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

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5 Figure 5 shows the set-up of apparatus to investigate the electrolysis of0.0001 moldm-3 sodium chloride solution.

FIGURE 5

(a) Name all the anions present in the solution.

………………………………………………………………………………………[1 mark]

(b) What is the energy change that occurs in the electrolysis process?

………………………………………………………………………………………[1 mark]

(c) (i) Name the gas collected in the test tube at electrode X.

………………………………………………………………………………………[1 mark ]

(ii) Write the half equation for the reaction at electrode X.

………………………………………………………………………………………[1 mark]

(iii) Explain how to confirm the gas produced at electrode X.

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………[2 marks]

Dilute sodiumchloride solution

0.0001 moldm-3

sodium chloridesolution

Carbonelectrode Y

Carbonelectrode X

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(d) What ion is discharged at electrode Y? Explain your answer.

.……………………………………………………………………………………...

.……………………………………………………………………………………...

………………………………………………………………………………………[2 marks ]

(e) The volume of gas collected at electrode Y is 30 cm3.Given that Avogadro number is 6.02 1023 mol-1 and 1 mol of gas occupies avolume of 24 dm3 mol-1 at room condition.

(i) Calculate the number of mole of the gas produced.

[1 mark]

(ii) What is the number of gas molecules collected?

[1 mark]

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6 Figure 6 shows four test tubes contain dry glacial ethanoic acid, aqueous solution ofethanoic acid, dilute hydrochloric acid and aqueous solution of X.

P Q

FIGURE 6

(a) (i) State the colour change of the litmu

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

(ii) Write the formula of ion which caupaper.

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

(b) Is there any changes of colour of the l

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

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

(c) Table 6 shows the pH value of aqueohydrochloric acid of the same molari

Type of acid aqueous solutioethanoic acid

Molarity 0.1 moldm-3

pH value 1.0TAB

Explain why the pH value of aqueouspH value of dilute hydrochloric acid.

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

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

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

Aqueous

Bluelitmuspaper

Dry glacialethanoicacid

Bluelitmuspaper

Aqueoussolution ofethanoic acid0.1 moldm-3

Dilutehydrochloricacid

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R S

s paper in test tubes Q and R.

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

sed the colour change of the litmus

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

itmus paper in test tube P? Explain why.

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

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

us solution of ethanoic acid and dilutety.

n of dilute hydrochloricacid

0.1 moldm-3

2.9LE 6

solution of ethanoic acid is higher than the

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

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

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

solutionof X

Bluelitmuspaper

0.1 moldm-3

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(d) Calcium carbonate powder is added into test tube R. Write the chemical equationfor the reaction that takes place.

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

(e) Aqueous solution of X is an acidic solution. As a chemistry student, describebriefly how you are able to prove that X is an acidic solution. You are not allow touse litmus paper, pH meter or any indicators.

Procedure:

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

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

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

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

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

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

Observation:

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

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

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Section B[20 marks]

Answer any one question.The time suggested to answer this section is 30 minutes.

7 (a) What is meant by “melting point”?During the melting of naphthalene, the temperature remains constant even though heatis applied. Explain why.

[4 marks]

(b)

Describe the change of the kinetic energy, arrangement and the forces of attractionbetween the particles at the following states: before condensation during condensation after condensation

[10 marks]

(c) Figure 7 shows the electron arrangement of ion Y3+.

FIGURE 7

(i) Calculate the nucleon number of atom Y. [2 marks]

(ii) Y reacts with oxygen to form oxide Y, with the formula Y2O3.The chemical equation for reaction Y with oxygen is show as:4Y + 3O2 2Y2O3.Given that the relative atomic mass of Y = 27 and O = 16.

Calculate the mass of oxide Y, Y2O3 formed when 10.8 g Y is completely burnt inoxygen.

[4 marks]

Condensation is the process where a gas changes to itsliquid state at a certain temperature and pressure whenit is cooled.

14 n

e

e

ee

ee

e e

e e3+

n neutrone electron

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8 (a) Helium, He42 exists as a monoatomic gas whereas chlorine, Cl35

17 exists as a diatomic

gas. Explain why. [4 marks]

(b) Table 8.1 shows the proton number of magnesium, chlorine and carbon.

TABLE 8.1

(i) Carbon reacts with chlorine to form a compound.What type of compound formed?Draw the electron arrangement to show the chemical bond in the compound.

[3 marks]

(ii) Describe how ionic bond is formed between magnesium and chlorine atoms.[7 marks]

(c) Figure 8 shows the set-up of apparatus to investigate the electrical conductivity ofsolid and solution of sodium chloride, NaCl.

FIGURE 8

Table 8.2 shows the result of the two experiments.

TABLE 8.2

(i) Compare the electrical conductivity of solid and solution of sodium chloride,NaCl. Explain why the results of Experiment I and II are different. [4 marks]

(ii) Calculate the mass of sodium chloride, NaCl in 50 cm3 of 0.2 moldm-3 sodiumchloride solution.Given that the molar mass of NaCl = 58.5 gmol1

[2 marks]

Element Magnesium Chlorine CarbonProtonnumber

12 17 6

Experiment I IICompound Sodium chloride Sodium chlorideState of compound Solid AqueousObservation Bulb does not light up Bulb lights up

Bulb

Electrodecarbon

Sodiumchloride

Electrodecarbon

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Section C[20 marks]

Answer any one question.The time suggested to answer this section is 30 minutes.

9 (a) Reactive metal can be extracted from its ore by electrolysis. Aluminium is a reactivemetal. State how aluminium can be extracted from its ore, which contains aluminiumoxide.

[4 marks]

(b) Daniell cell is an example of a voltaic cell. In this cell, zinc and copper are used aselectrodes. Explain how a Daniell cell can produce electric current.Use a labelled diagram to explain your answer.

[6 marks]

(c) A student intends to electroplate an iron spoon with a suitable metal.Design a laboratory experiment to electroplate the iron spoon.Your answer should consist of the following:

Chemicals required Procedure of the experiment Diagram showing the set-up apparatus Half equations involved in the reaction Observations

[10 marks]

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Cation Anion test

10 (a) An insoluble salt can be prepared by the precipitation reaction.Give an example of an insoluble salt and suggest two solutions to prepare the insolublesalt.Write the ionic equation to represent the precipitation reaction.

[4 marks]

(b) Figure 10 shows an incomplete flow chart of cation and anion tests for salt X.

FIGURE 10

Use the reagents listed below to confirm that salt solution of X contains Zn2+ ions andSO4

2- ions.

[6 marks]

(c) Copper(II) sulphate is a soluble salt. Describe how to prepare a dry sample ofcopper(II) sulphate in the laboratory.

Your answer should consist of the following: Chemicals required Procedure of the preparation Chemical equation involved in the reaction

[10 marks]

END OF QUESTION PAPER

SO42-Zn2+

REAGENTS Sodium hydroxide solution Ammonia solution Hydrochloric acid Barium chloride solution

Salt solutionof X

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1

BAHAGIAN SEKOLAHKEMENTERIAN PELAJARAN MALAYSIA

CHEMISTRY FORM 4FINAL EXAM 2006

MARKING SCHEME

PAPER 2

2

Marking Scheme Paper 2Section A

QuestionNumber

Explanation Mark

1(a) A,B 1

(b) 2.8 1

(c) D3+ 1

(d)(i) C 1

(ii) Form complex ions // Act as catalysts // Exhibit different oxidationnumbers

1

(e) E // H 1

(f) F, A, G, E, D, B 1

(g)(i) 2A + 2H2O 2AOH + H2 1

(ii) alkaline 1

(h) 1. Atom E has a smaller size2. The attraction forces between nucleus and electrons are strongerOR1. Atom H has a bigger size2. The attraction forces between nucleus and electrons are weaker.

11

211

Total 11

3

QuestionNumber

Explanation Mark

2 (a) Formula that gives the actual number of atoms of each element thatare present in one molecule of the compound

1

(b) C6H12O6 1

(c) 1. No2. Exits as molecules

11 2

(d) (i) C H O1. Mole 52.2/ 12 13.0 /1 34.8/16

4.35 13.0 2.1752. Ratio 2 6 13. Empirical formula = C2H6O

1

11 3

(ii) [2(12) + 6(1) + (16)]n = 46n = 1

Molecular formula = C2H6O11 2

Total 9

QuestionNumber

Explanation Mark

3(a)(i) Contact Process 1

(ii) Sulphur react with oxygen 1

(iii) Vanadium (V) oxide 1

(iv) 2 SO2 + O2 2SO3 1

(v) H2S2O7 1

(b)(i) Tin 1

(ii)

1

1

2(iii) 1. Tin atoms with different size disturb the orderly arrangement

of copper atoms.2. Tin atoms prevent the layer of copper atoms from sliding.

1

1 2

Total 10

Tin atom

CopperatomsPure copper Brass

4

QuestionNumber

Explanation Mark

4(a) Neutralization 1

(b) H2SO4 + 2KOH K2SO4 + H2O 1

(c)(i) K+ , OH-, SO42- 1

(ii) K+ , SO42-, H+ 1

(d) 5.0 cm3 1

(e) 1. MaVa = aMbVb b

2. 1.0 (5.0) = 1Mb (25) 2

3. Mb = 2(1.0)(5.0) = 0.4 mol dm-3

25

1

1

1 3

(f) 1. 10.0 cm3

2. nitric acid is monoprotic acid / sulphuric acid is diprotic acid11 2

Total 10

QuestionNumber

Explanation Mark

5(a) Chloride, hydroxide 1

(b) Electrical energy to chemical energy 1

(c)(i) Hydrogen 1

(ii) 2H+ + 2e H2 1

(iii) 1. Lower a lighted wooden splinter2. A “pop” sound is heard

11 2

(d) 1. Hydroxide ions // OH-

2. The concentration of hydroxide ions is higher11 2

(e)(i) 30 / 0.03 / 0.0012524000 24

1

(ii) 0.00125 x 6.02 x 1023 / 7.525 x 1020 1

Total 10

5

QuestionNumber

Explanation Mark

6(a) (i) Blue to red 1

(ii) H+ 1

(b) 1. No2. No water / H+ ions

11 2

(c) 1. Ethanoic acid is weak acid, hydrochloric acid is strong acid2. The concentration of H+ ions in ethanoic acid is lower / The

concentration of H+ ions in hydrochloric acid is higher.

11 2

(d) CaCO3 + 2HCl CaCl2 + CO2 + H2O 1

(e) 1. [ Material : name of reactive metal / name of carbonate salt]2. [To test gas produced]3. [Observation]Example 1Procedure:1. Magnesium ribbon is added into the aqueous solution X2. Lower a lighted wooden splinterObservation:A “pop” sound is heard

Example 2Procedure:1. Calcium carbonate is added into the aqueous solution X2. Passing the gas through lime waterObservation:Lime water turns milky

11 21

11 2

1

11 2

1

Total 10

6

Section B

QuestionNumber

Explanation Mark

7 (a) Melting point is the temperature at which a solid changes into aliquid at a particular pressure.Because the energy absorbed by the naphthalene is used to overcomethe forces of attraction between the molecules of naphthalene.

1111 4

7(b) Before condensation The kinetic energy is high The particles are very far apart from each other The attraction forces between particles are very weak.

During condensation The kinetic energy decreases The particles begin to move closer toward one another

/ the distance between the particles decrease The attraction forces between particles become stronger.

After condensation The kinetic energy is low The particles are packed closely together in an orderly manner The attraction forces between particles are strong.

111

11

1

111+11 10

7(c)(i) Proton number = 13Nucleon number = 14 + 13 = 27

11 2

7(c)(ii)Number of moles of Y =

27

8.10= 0.4

Number of moles of Y2O3 = 0.4 ÷ 2 = 0.2Relative formulas mass of Y2O3 = 2(27) + 3(16) = 102Mass of Y2O3 = 0.2 102 = 20.4 g

1

111 4

Total 20

7

QuestionNumber

Explanation Mark

8 (a) Helium atom has two electrons in its valence shell / helium atomhas achieved a duplet electron arrangement.Helium atom will not gain, lose nor share electrons with other atoms.

Chlorine atom has an electron arrangement of 2. 8. 7, needs oneelectron to achieve the octet electron arrangement.Thus, two chlorine atoms share one pair of electrons so that bothatoms can achieve the octet electron arrangement.

1

1

1

1 4

8(b)(i) Covalent compound 1

1 + 1

3

8(b)(ii) A magnesium atom with an electron arrangement of 2.8.2 //donates 2 valence electron to achieve the stable / octet electronarrangement // 2. 8.A positive magnesium ion, Mg2+ is formed.Two chlorine atoms, each with an electron arrangement of 2.8.7accepts 1 electron to achieve the stable octet electron arrangement//2. 8. 8.A negative chloride ion, Cl is formed.Mg2+ and Cl ions are attracted to each other by a strongelectrostatic force.

11

111

11 7

8(c)(i) Solid sodium chloride cannot conduct electricity, sodium chlorideaqueous solution can conduct electricity.In solid state, sodium ions and chloride ions are held together bystrong electrostatic forces // are fixed in their positionand cannot move freely.In aqueous state, sodium ions and chloride ions are free to move.This enables ions to be discharge at anode and cathode.

1

1

11 4

8(c)(ii) Number of moles of NaCl = 0.2 0.05 = 0.01

Mass of 0.01 mole of NaCl = 0.01 58.5 = 0.585 g

1

1 2

Total 20

C ClCl

Cl

Cl

8

Section C

QuestionNumber

Explanation Mark

9 (a) Cryolite is added to aluminium oxide to lower its melting point.Molten aluminium oxide is electrolysed using carbon electrodes.Aluminium ions are discharged at cathode. // Al3+ + 3e AlOxide ions are discharged at anode.// 2O2 O2 + 4e

1111 4

9(b)

Zinc is more electropositive than copper.Zinc atom releases electrons to form zinc ionsolution.

//Zn(s) Zn2+(aq) +

The electrons flow from zinc electrode to coexternal circuit.

At the copper electrode, the electrons are acions, Cu2+ to form copper atoms.

//Cu2+(aq) + 2e C

1+1

Zinc plate

Copper plate

Zinc sulphate solution(1.0 moldm-3) Salt bridge

Copper (II) sulphate solution

s, Zn2+ in zinc sulphate

2e

pper electrode through

cepted by the copper(II)

u(s)

11

1

1 6

(1.0 moldm-3)

9

9(c) Silver can be used to electroplate the iron key.The electrolyte is silver nitrate solution, [0.5 moldm-3].[or other suitable metal and electrolyte]The silver electrode is connected to positive terminal of battery // actas anode.The iron spoon is connected to negative terminal of battery // act ascathode.

The switch is turned on.AnodeHalf equation : Ag(s) Ag+

(aq) + e

Observation : Silver electrode becomes thinner.

CathodeHalf equation : Ag+

(aq) + e Ag(s)

Observation : A thin layer of shiny grey solid is deposited on theiron spoon.

11

1

1

1+1

1

1

1

1

1 [11]

Max. 10Total 20

Iron spoon

Silver

Silver nitrate solution,0.5 moldm

-3

10

QuestionNumber

Explanation Mark

10 (a) [Name any insoluble salt][Name any two suitable solution][Write correct ionic equation]

Example:Lead(II) sulphateLead(II) nitrate solution and sodium sulphate solutionPb2+ + SO4

2 PbSO4

11+11 4

10(b) Test for Zn2+ ion

Procedure I: A few drops of sodium hydroxide solution are added into the

salt solution of X until in excess.Observation : White precipitate dissolved in excess sodium hydroxide

solution to produce a colourless solution.

Procedure II: A few drops of ammonia solution are added into the salt solution

of X until in excess.Observation : White precipitate dissolved in excess ammonia solution to

produce a colourless solution.

Inference:Zn2+ ion is present

Test for SO42+ ion

5 cm3 of hydrochloric acid is added into the salt solution of Xfollow by 2 cm3 of barium chloride solution.

Observation: White precipitate is formed.

Inference:SO4

2+ion is present.

1

1

1

1

1

1 6

11

10(c) Chemicals :sulphuric acid and copper(II) oxide / copper(II) carbonate

50 cm3 of 1.0 moldm-3 sulphuric acid is pour into a beaker andwarmed carefully

Copper(II) oxide powder is added a little at a time into the acidusing spatula.

The mixture is stir well with a glass rod. Copper(II) oxide powder is added continuously until some of it

no longer dissolves. The mixture is filtered to remove the excess copper(II) oxide. The filtrate is pour into an evaporating dish and heated gently to

produce a saturated solution / heated until the filtrate isevaporated to about 1/3 of its original volume.

The saturated solution is then allowed to cool to roomtemperature for crystallisation to occur.

The copper(II) sulphate crystals are filtered and dry by pressingthem between a few pieces of filter paper.

H2SO4 + CuO CuSO4 + H2O

1

1

1

11

1

1

1

1

1 [10]

Total 20

END OF MARKING SCHEME OF PAPER 2