Kedah Chemistry Trial 2010 (NO BAHASA MELAYU)

27
CONFIDENTIAL*/SULIT* [Turn over(Lihat sebelah) SULIT * PEPERIKSAAN PERCUBAAN BERSAMA STPM 2010 Anjuran Bersama JABATAN PENDIDIKAN KEDAH DARUL AMAN DAN PERSIDANGAN KEBANGSAAN PENGETUA-PENGETUA SEKOLAH MENENGAH MALAYSIA (PKPSM) KEDAH Instructions to candidates: DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO. There are fifty questions in this paper. For each question, four suggested answers are given. Choose one correct answer and indicate it on the multiple-choice answer sheet provided. Read the instructions on the multiple-choice answer sheet very carefully. Answer all questions. Marks will not be deducted for wrong answers. Arahan kepada calon: JANGAN BUKA KERTAS SOALAN INI SEHINGGA ANDA DIBENARKAN BERBUAT DEMIKIAN. Ada lima puluh soalan dalam ujian ini. Tiap-tiap soalan diikuti oleh empat pilihan jawapan. Anda dikehendaki memilih satu jawapan yang paling tepat dan menandakannya pada Borang Jawapan Aneka Pilihan yang berasingan. Baca arahan pada Borang Jawapan Aneka pilihan itu dengan teliti. Jawab semua soalan. Markah tidak akan ditolak bagi jawapan yang salah. Jumlah markah anda dalam ujian ini ialah bilangan soalan yang dijawab dengan betul. This question paper consists of 25 printed pages and 1 blank page. (Kertas soalan ini terdiri daripada 25 halaman bercetak dan 1 halaman kosong.) *This question paper is CONFIDENTIAL until the examination is over. *Kertas soalan ini SULIT sehingga peperiksaan kertas ini tamat STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL 962/1 STPM 2010 TRIAL EXAMINATION CHEMISTRY (KIMIA) PAPER 1 (KERTAS 1) One hour and forty-five minutes (Satu jam empat puluh lima minit) http://edu.joshuatly.com/ http://www.joshuatly.com/

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Kedah Chemistry Trial 2010 (NO BAHASA MELAYU)

Transcript of Kedah Chemistry Trial 2010 (NO BAHASA MELAYU)

Page 1: Kedah Chemistry Trial 2010 (NO BAHASA MELAYU)

CONFIDENTIAL*/SULIT*

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PEPERIKSAAN PERCUBAAN BERSAMA STPM 2010

Anjuran Bersama

JABATAN PENDIDIKAN KEDAH DARUL AMAN

DAN

PERSIDANGAN KEBANGSAAN PENGETUA-PENGETUA

SEKOLAH MENENGAH MALAYSIA (PKPSM) KEDAH

Instructions to candidates:

DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO.

There are fifty questions in this paper. For each question, four suggested answers are given. Choose one correct answer and indicate it on the multiple-choice answer sheet provided.

Read the instructions on the multiple-choice answer sheet very carefully. Answer all questions. Marks will not be deducted for wrong answers. Arahan kepada calon:

JANGAN BUKA KERTAS SOALAN INI SEHINGGA ANDA DIBENARKAN BERBUAT DEMIKIAN. Ada lima puluh soalan dalam ujian ini. Tiap-tiap soalan diikuti oleh empat pilihan jawapan. Anda dikehendaki memilih satu jawapan yang paling tepat dan menandakannya pada Borang Jawapan Aneka Pilihan yang berasingan. Baca arahan pada Borang Jawapan Aneka pilihan itu dengan teliti. Jawab semua soalan. Markah tidak akan ditolak bagi jawapan yang salah. Jumlah markah anda dalam ujian ini ialah bilangan soalan yang dijawab dengan betul. This question paper consists of 25 printed pages and 1 blank page. (Kertas soalan ini terdiri daripada 25 halaman bercetak dan 1 halaman kosong.) *This question paper is CONFIDENTIAL until the examination is over. *Kertas soalan ini SULIT sehingga peperiksaan kertas ini tamat

STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL STPM TRIAL

962/1 STPM 2010

TRIAL EXAMINATION

CHEMISTRY (KIMIA)

PAPER 1 (KERTAS 1)

One hour and forty-five minutes (Satu jam empat puluh lima minit)

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Section A

Four suggested answers labelled A, B, C and D are given for each question. Choose one correct answer.

1 Which species has the same number of neutrons and electrons? A 9Be B 23Na+

C 19F D 18O2- 2 Which electronic transition emits electromagnetic radiation with the highest energy? A n2 n1

B n5 n2

C n8 n2

D n9 n3

3 Which one of the following pairs have the same shape?

A CO and I3−

B CO2 and SO2

C AlCl3 and PH3 D CH3

+ and NH4+

4 5.00 g of a mixture of magnesium and zinc was added to excess of dilute sulphuric acid. If 3.0 dm3 of hydrogen gas was produced, what is the percentage composition of zinc in the mixture? [Relative atomic mass: Mg, 24; Zn, 65; 1 mole of gas occupies 24.4 dm3 at room temperature]

A 37.6% B 50.0% C 65.0% D 80.3% 5 The boiling points of the Group 17 hydrides are shown in the graph below. Which statement explains the highest boiling point of HF?

A The HF molecule is polar. B Hydrogen bonding exists between HF molecules. C HF is ionic while the other hydrides are covalent. D Fluorine is the most electronegative element in Group 17.

x

x x

x

HF HCl HBr HI

Boiling point/oC

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6 The rate equation of a reaction is as follows.

Rate = k[A]

Which one of the following graphs represent the above reaction? 7 At 273 K, 30% of dinitrogen tetroxide in a closed container decomposes into nitrogen dioxide according to equation below. N2O4 (g) 2NO2 (g) If the total pressure in the equilibrium mixture is P, what is the value of the equilibrium

constant, Kp, of the system?

A 7

6P B

13

6P C

70

36P D

91

36P

8 In a chemical process, XH3 is produced as follows.

X2 (g) + 3H2 (g) 2XH3 (g) H = -92 kJ mol-1

Which of the following conditions would produce the highest yield of XH3 at equilibrium?

Pressure Temperature Catalyst

A High High Present

B High High None

C Low Low None

D High Low None

Time /s

[A]/mol dm-3 A

Time /s

D 31 dmmol/

]A[

1

C Rate/ mol dm-3 s-1

Time /s

[A]/mol dm-3

Time /s

B

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9 Barium sulphate, BaSO4, and calcium sulphate, CaSO4, are shaken together in water, and a saturated solution is produced. Which statement is true? [Ksp for BaSO4 is 2.3 x 10-7 mol2 dm-6, Ksp for CaSO4 is 3.4 x 10-6 mol2 dm-6 at 298 K]

A BaSO4 is more soluble than CaSO4. B The common ion effect causes BaSO4 and CaSO4 to be more soluble. C The solubilities of BaSO4 and CaSO4 will decrease with the addition of some MgSO4. D BaSO4 and CaSO4 will dissolve when dilute hydrochloric acid is added. 10 The partition coefficient of butanedioic acid between ether and water is 0.15. A solution of 10 g of butanedioic acid in 1 dm3 of water was extracted once by using 500 cm3 ether. What is the percentage of butanedioic acid left in the aqueous phase?

A 90% B 93% C 95% D 97% 11 A silver nitrate solution is electrolysed for 30 minutes using carbon electrodes. 0.10 g of silver was deposited at the cathode. What is the current used? [Faraday’s constant = 9.65 x 104 C mol-1; Relative atomic mass of Ag = 108]

A 2.5 x 10-2 A B 5.0 x 10-2 A C 7.5 x 10-2 A D 1.0 x 10-2 A 12 The diagram below shows the Born-Haber cycle for sodium bromide. Which combination is correct?

Enthalpy change x / kJ mol-1

A First ionisation energy of sodium +490

B First ionisation energy of sodium +230

C Atomisation energy of sodium +360

D Atomisation energy of sodium +401

NaBr(s) Na+(g) + Br-(g)

Na(s) + 2

1 Br2(l) Na(g) + Br(g)

+736 kJ mol-1

376 kJ mol-1

+205 kJ mol-1

x 335 kJ mol-1

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13 The pH range for same indicators are shown below.

Indicators pH range

Methyl Red 4.2 – 6.3

Methyl orange 2.8 – 4.1

Phenolphthalein 8.3 – 10.1

Bromothymol blue 6.1 – 7.5 Which indicator is the most suitable in the titration between 1.0 mol dm-3 of ethanedioic acid with 1.0 mol dm-3 of aqueous potassium hydroxide?

A Methyl red B Methyl orange C Phenolphthalein D Bromothymol blue 14 What is the pH of a buffer solution that contains 16.4 g of sodium ethanoate in 500 cm3 of a 0.20 mol dm-3 ethanoic acid solution?

[Ka for ethanoic acid = 1.80 x 10-5 mol dm-3; Relative molecular mass of sodium ethanoate is 82] A 2.13 B 4.44 C 5.05 D 5.20 15 The boiling point-composition diagram of a mixture of two liquids, Y and Z, is shown below.

Which statement is true?

A It is an endothermic reaction when Y is mixed with Z. B The azeotropic mixture contains 50% of Y and 50% of Z. C The mixture shows a positive deviation from Raoult’s Law. D Fractional distillation on 50% of Y leaves a residual liquid with composition M .

Boiling point/oC

100% Y

100% Z

M Composition

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16 The elements X, Y and Z are in Period 2 in the Periodic Table and they have the following properties. (i) X has a giant molecular structure. (ii) Y is a metal. (iii) Z is a simple molecule.

Which statement is true regarding X, Y and Z?

A Element Y is an oxidising agent. B Electronegativity increases in the order of X, Y, Z. C Chlorides of X, Y and Z liberate white fumes with water. D The order of increasing basic character of their oxides is Z, X, Y. 17 The solubilities of two sulphates are given below.

Compound Solubility (g per 100 g solution) at 20oC

CaSO4 BaSO4

2.3 x 10−1 2.3 x 10−4

Which statement best explains the above data?

A BaSO4 has a lower lattice energy than that of CaSO4. B The size of the Ba2+ ion is bigger than that of the Ca2+ ion. C Barium has a lower ionisation energy than that of calcium. D Ba2+ ion has a lower hydration energy than that of Ca2+ ion. 18 Which of the following is not explained by the high charge density of Al3+ ion?

A Formation of the dimer, Al2Cl6 B Formation of [Al(H2O)6]

3+ ion C Amphoteric character of aluminium oxide D Acidic character of an aluminium salt solution 19 A tetrachloride of Group 14, XCl4, has the following properties. (i) Easily hydrolysed (ii) Decomposes at room temperature according to the equation

XCl4 → XCl2 + Cl2 X could be

A germanium B carbon C lead D silicon 20 Which statement is true of nitrogen dioxide?

A It is linear in shape. B The nitrogen atom has an odd electron. C Its enthalpy of formation is endothermic. D It is insoluble in water. http://edu.joshuatly.com/

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21 Which statement is correct?

A Ammonium nitrate forms an alkaline solution. B All nitrogen oxides are soluble in water forming acids. C Concentrated nitric(V) acid releases hydrogen gas from metals. D All Group 2 nitrates are decomposed by heat to form nitrogen dioxide gas. 22 Which statement is not true about the halogens?

A They exist as diatomic molecules. B Colour intensity increases down the group. C Solubility in water decreases down the group. D Reactivity with hydrogen increases down the group. 23 A solid X shows the following properties. (i) When heated strongly, it gives a gas which supports combustion. (ii) When an aqueous solution of the residue from (i) is shaken with aqueous chlorine

in tetrachloromethane, a purple layer is obtained. Solid X could be

A KBr B KI C KClO3 D KIO3 24 Most transition metals are heterogeneous catalysts. Which property of transition metals explains their use as heterogeneous catalysts?

A They are reactive metals. B They are reducing agents. C They have empty d–orbitals. D They exhibit variable oxidation states. 25 What type of isomerism would be exhibited by CrCl3.6H2O?

A Structural only B Structural and geometric C Structural and optical D Geometric and optical 26 50 cm3 of a mixture of methane and ethane are placed in a container. The mixture undergoes combustion in 200 cm3 of excess oxygen. The volume of the gases after combustion is 134 cm3. When the gases are passed through aqueous potassium hydroxide solution, the volume decreases to 52 cm3. What is the volume of methane in the mixture? A 18 cm3 B 25 cm3 C 32 cm3 D 38 cm3

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27 Benzene reacts with a mixture of concentrated nitric(V) acid and concentrated sulphuric(VI) acid at 55 oC to form a yellow oil. When heated to 90 oC, compound X is formed. Compound X could be

28 Ethylbenzene, C6H5CH2CH3, is heated with alkaline potassium manganate(VII) solution, and dilute hydrochloric acid is added to the resulting solution. What is the final product formed after acidification ?

A C6H5OH B C6H5CHO C C6H5COOH D C6H5CH2COOH 29 An aromatic compound P has the molecular formula C8H9Cl. When P is heated with acidified potassium manganate(VII) solution, the compound C8H6O4 is formed. P could be 30 Which compound reacts with ethylmagnesium bromide to produce 2,3-dimethyl-3-pentanol?

A Pentanal B 2-butanone C 3-methyl-2-butanone D 2-methyl-3-pentanone 31 Chloroethane reacts with aqueous sodium hydroxide to form ethanol according to the following equation. CH3CH2Cl + OH‾ → CH3CH2OH + Cl‾

What is the rate equation for the reaction ?

A Rate = k [OH‾] B Rate = k [CH3CH2Cl] C Rate = k [CH3CH2OH] [Cl‾] D Rate = k [CH3CH2Cl] [OH‾]

A NO2 B NO2

NO2

C NO2

NO2

D NO2

NO2

A CH2CH2Cl

B CH2Cl CH3

C2H5 Cl C

D CH3 Cl

CH3

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32 An organic compound S has the following chemical properties.

Releases white fumes with ethanoyl chloride Forms a yellow precipitate with alkaline iodine solution Forms butanone when heated with acidified potassium manganate(VII) solution

S could be

A (CH3)2CHCOCH3 B CH3CH2CH2CH2OH C CH3CH2CH(OH)CH3

D CH3CH2CH(OH)CH2CH3 33 The matsutake mushroom is a favourite delicacy used in many Japanese dishes. The aroma of this mushroom is caused by the compound methyl cinnamate, which can be prepared in the laboratory according to the following reaction scheme. What are the reagents used in Step 1 and Step 2?

Step 1 Step 2 A AlCl3 CH3COOH B PCl3 CH3OH C HCl CH3OH D PCl5 CH3COCl

34 Phenol reacts with bromine water to form a white precipitate of 2,4,6-tribromophenol. What is the mechanism of this reaction?

A Electrophilic addition B Electrophilic substitution C Nucleophilic addition D Nucleophilic substitution 35 A compound P has the following properties.

Forms a white precipitate with alcoholic silver nitrate solution Forms an orange precipitate with 2,4-dinitrophenylhydrazine Forms a silver mirror with Tollens’ reagent

Compound P could be

Step 1 CH=CH–C–OH

O Step 2

CH=CH–C–Cl

O

CH=CH–C–OCH3

O

A CH2Cl

C = O

B CH2Cl

C = O

H

D CH3

C = O

Cl

C CH3

C = O

H

Cl

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36 Which reagent can be used to differentiate between butanal and butanone?

A Phosphorus(V) chloride B Alkaline iodine solution C Hydrogen, nickel at 180 oC D 2,4-dinitrophenylhydrazine solution 37 An aromatic compound Z reacts with ammonia to form a white precipitate. Z could be 38 Novocaine is an anaesthetic used in surgery. Its structure is shown below. Novocaine is expected to

A dissolve in dilute hydrochloric acid B form a yellow oil with nitric(III) acid C form a silver mirror with Tollens’ reagent D form an orange precipitate with 2,4-dinitrophenylhydrazine solution 39 Aniline is used to prepare a yellow dye according to the following equation. In an experiment, 5.00 g of aniline was used to prepare the dye. What is the mass of the dye obtained ? [Relative atomic mass : H=1, C=12, N=14, O=16]

A 10.2 g B 10.6 g C 10.8 g D 11.4 g

A OH

B Br

C CH2OH

D C−Cl

O

CH2

C – O – CH2 – CH2 – N – CH2 – CH3

O

CH3

NH2 + HNO2 + HCl + OH N=N OH + HCl + 2H2O

Yellow dye Aniline

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40 The repeating unit of a polymer is shown below. Which compound(s) can be used to prepare the above polymer?

A CH2ClCH=C(CH3)CH3

B CHCl=CHC(CH3)=CH2 C CHCl=CH2 and CH3CH=CH2 D CH2ClCH3 and CH3CH2CH3

Section B For each of the questions in this section one or more of the three numbered statements 1 to 3 may be correct. The responses A to D should be selected as follows.

A B C D

1 only is correct.

1 and 2 only are correct.

2 and 3 only are correct.

1, 2 and 3 are correct.

41 A gas is compressed by increasing the pressure at constant temperature from 10 atm to 20 atm . Its volume decreases from 200 cm3 to 85 cm3. Which statement(s) explain(s) this behaviour?

1 The gas dimerises. 2 The gas behaves non-ideally. 3 There are strong intermolecular forces between the gas particles. 42 The rate determining step of a reaction mechanism is one

1 that is the slowest 2 with the highest activation energy 3 that involves a catalyst 43 Dissociation of water molecules occurs according to the equation below.

H2O (ℓ) H+(aq) + OH- (aq)

The ionic product of water, Kw, is 0.11 x 10-14 mol2 dm-6 at 0 oC and 1.00 x 10-14 mol2 dm-6 at 25 oC. From the above information, it can be deduced that 1 H of the above reaction is negative 2 the pH of pure water is less than 7 at 100 oC 3 electrical conductivity of water increases with temperature

─ C ─ C = C ─ C ─

H

Cl

H

CH3

H

H

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A B C D

1 only is correct.

1 and 2 only are correct.

2 and 3 only are correct.

1, 2 and 3 are correct.

44 The diagram below shows the arrangement of an electrochemical cell.

The standard electrode potentials of some metals are given below.

Electrode system E/V

Ag+(aq)/Ag(s) +0.80

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

Fe2+(aq)/Fe(s) −0.44

Zn2+(aq)/Zn(s) −0.76

Which compound can be used as Mx+ solution?

1 AgNO3 2 CuSO4 3 ZnSO4 45 Which statement(s) explain(s) the increasing thermal stability of the carbonates of Group 2 elements (beryllium to barium) when descending the group?

1 The radius of the cation increases. 2 The charge density of the O2− ion is higher than that of the CO3

2− ion. 3 The polarising power of the cation increases. 46 Which of the following account(s) for the use of aluminium as high voltage electric cables?

1 Low density 2 Good conductor of electricity 3 Good reflector of heat energy 47 The following equation shows the reaction that occurs when aqueous potassium thiocyanate, KSCN, is added to a solution containing iron(III) ions.

[Fe(H2O)6]3+(aq) + SCN–(aq) → [Fe(H2O)5SCN]2+(aq) + H2O(l)

Which statement(s) is/are true about the reaction ?

1 H2O is a weaker ligand than SCN–. 2 The brown solution turns colourless. 3 The oxidation number of iron in [Fe(H2O)5SCN]2+ is +2.

Iron

V

Metal M

FeSO4(aq) 1.0 mol dm-3

Salt bridge

Deposit of metal M

Mx+ solution 1.0 mol dm-3

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A B C D

1 only is correct.

1 and 2 only are correct.

2 and 3 only are correct.

1, 2 and 3 are correct.

48 Which molecule(s) show(s) geometric isomerism? 1 CHCl = CHBr 2 CH3CH2CH = CHBr 3 CH2 = CHCH = CH(CH3) 49 Geraniol is a compound extracted from geranium oil. Its structure is shown below.

Which statement(s) is/are true about geraniol ?

1 It is optically inactive. 2 It decolourises a solution of bromine in tetrachloromethane 3 It forms an alkane when heated with hydrogen in the presence of nickel. 50 In the polymerisation of propene to produce polypropene, three types of polymer structures could be obtained, depending on the conditions of the reaction. Which structure(s) would be obtained if Ziegler-Natta catalyst is used?

1

─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─

H

H CH3 CH3 CH3 CH3

H H H H H H H H

H H H H CH3

H

2

─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─

H

H CH3

CH3

CH3

CH3 H H

H

H H H

H

H

H H H H CH3

H

3

─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─ C ─

H

H CH3

CH3

CH3 CH3

H H

H

H

H

H H

H H H

H

H

CH3 H

CH3─C=CHCH2CH2C=CHCH2OH

CH3 CH3

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

PEPERIKSAAN PERCUBAAN BERSAMA STPM 2010

ANJURAN BERSAMA

JABATAN PELAJARAN NEGERI KEDAH DARUL AMAN

DAN

PERSIDANGAN KEBANGSAAN PENGETUA-PENGETUA

SEKOLAH MENENGAH MALAYSIA (PKPSM) KEDAH Instructions to candidates:

DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE

TOLD TO DO SO.

Answer all questions in Section A. Write your answers in the spaces provided. All working should be shown. For numerical answers, units should be quoted wherever they are appropriate.

Answer any four questions in Section B. Write your answers on your own answer sheets. Begin each answer on a fresh sheet of paper and arrange your answers in numerical order. Tie your answer sheets to this question paper. Answers may be written in either English or Malay.

A Data Booklet is provided.

Arahan kepada calon: JANGAN BUKA KERTAS SOALAN INI SEHINGGA ANDA DIBENARKAN BERBUAT DEMIKIAN. Jawab semua soalan dalam Bahagian A. Tulis jawapan anda dalam ruang yang disediakan. Semua kerja hendaklah ditunjukkan. Bagi jawapan berangka unit hendaklah dinyatakan di mana-mana yang sesuai.

Jawab mana-mana empat soalan dalam Bahagian B. Tulis jawapan anda pada helaian jawapan anda sendiri. Mulakan setiap jawapan pada helaian kertas yang baru, dan susun jawapan anda mengikut tertib berangka. Ikat helaian jawapan anda bersama dengan kertas soalan ini.

Jawapan boleh ditulis dalam Bahasa Inggeris atau Bahasa Melayu. Buku Data dibekalkan.

This question paper consists of 15 printed pages and 1 blank page. (Kertas soalan ini terdiri daripada 15 halaman bercetak dan 1 halaman kosong.) STPM 962/2 [ Turn over (Lihat sebelah) * This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL* *Kertas soalan ini SULIT sehingga peperiksaan kertas ini tamat. SULIT*

962/2 TRIAL STPM 2010 (PERCUBAAN)

CHEMISTRY (KIMIA)

PAPER 2 (KERTAS 2)

Two and a half hours (Dua jam setengah)

For examiner’s use (Untuk kegunaan pemeriksa)

1

2

3

4

5

6

7

8

9

10

Total (Jumlah)

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Section A [40 marks] Answer all questions in this section.

1 (a) Hydrogen sulphide, H2S, is a foul-smelling gas released from volcanoes. (i) Draw a ‘dot-and-cross’ diagram to show the structure of the H2S molecule.

[1 mark] (ii) Predict the shape of the H2S molecule. ………………………………………………………………………………………………

[1 mark] (iii) Draw a labelled diagram to show the overlapping of orbitals in the H2S molecule.

[2 marks] (b) Both H2S and H2O are hydrides of Group 16 in the Periodic Table. (i) Explain the difference in the bond angle of the H2S and H2O molecules. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ……………………………………………………………………………………………….

[3 marks] (ii) H2S is a gas at room conditions whereas H2O is a liquid. Explain the difference in

terms of structure and bonding. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………..

[3 marks] 962/2 *This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*

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CONFIDENTIAL* 2 (a) The pH of orange juice is 3.5.

(i) Define pH. …………………………………………………………………………………………...............

[1 mark] (ii) Calculate the molar concentration of hydrogen ions in the orange juice.

[1 mark]

(b) Orange juice is a monoprotic acid. In a titration, 25.0 cm3 of the orange juice was exactly neutralised by 27.50 cm3 of 0.10 mol dm-3 sodium hydroxide solution using phenolphthalein as indicator. (i) Calculate the molar concentration of the acid in the orange juice.

[2 marks]

(ii) Explain the difference between the results obtained in (a)(ii) and that in (b)(i).

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

[2 marks] (iii) Calculate the acid dissociation constant, Ka, of the orange juice.

[2 marks] (iv) Why is phenolphthalein a suitable indicator for this reaction?

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

[2 marks] 962/2 *This question paper is CONFIDENTIAL until the examination is over: CONFIDENTIAL*

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3 (a) The standard electrode potentials, at 298 K, of some half-cells are given below. Half-cell E⊖/V

Ge4+(aq) + 2e− ⇌ Ge2+ (aq) −1.60

Sn4+(aq) + 2e− ⇌ Sn2+ (aq) +0.15

Pb4+(aq) + 2e− ⇌ Pb2+ (aq) +1.80

(i) Arrange the Ge4+, Sn4+ and Pb4+ ions in order of decreasing stability in aqueous solutions. ……………………………………………………………………………………………………

[1 mark] (ii) Which ion is the strongest reducing agent?

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

[1 mark] (iii) Which is more stable in aqueous solutions, Pb2+ or Pb4+ ? Explain your answer.

…………………………………………………………………………………………………… ……………………………………………………………………………………………………

[2 marks]

(b) An important application of glass is in the making of optical fibres. A laser beam can travel along an optical fibre which is as thin as human hair.

(i) State the main component of glass.

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

(ii) State one use of optical fibres.

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

(iii) In certain applications, optical fibres have many advantages over copper wires.

State two advantages of optical fibres over copper wires.

…………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………………

[2 marks] (iv) State the difference in the structure between glass and diamond.

…………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………………

[2 marks] 962/2 *This question paper is CONFIDENTIAL until the examination is over: CONFIDENTIAL*

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4 (a) 1,4-benzenedicarboxylic acid can be prepared from 1,4-dimethylbenzene. (i) State the reagent and write the equation for the reaction.

Reagent : …………………………………………………………………………….. [1 mark]

Equation : ……………………………………………………………………………..

[2 marks]

(ii) Explain why 1,4-dimethylbenzene undergoes electrophilic substitution reaction more readily than 1,4-benzenedicarboxylic acid. ………………………………………………………………………………………………… ………………………………………………………………………………………………...

[2 marks] (b) Part of the structure of a polymer is shown below.

O H O H — C— —N—C— —N—

(i) Write the structural formula of the monomer which forms the polymer.

[1 mark] (ii) The monomer is soluble in water but the polymer is not. Explain this statement. …………………………………………………………………………………………………… ……………………………………………………………………………………………………

[2 marks] (iii) State the type of polymerisation the monomer undergoes. …………………………………………………………………………………………………...

[1 mark] (iv) Write the structural formula of the product formed when the monomer reacts with

hydrochloric acid.

[1 mark] 962/2 *This question paper is CONFIDENTIAL until the examination is over: CONFIDENTIAL*

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Section B [60 marks]

Answer any four questions in this section.

5 (a) (i) Using the same axes, sketch the Maxwell-Boltzmann distribution curve for a sample of gas at 25 oC and 50 oC. [2 marks] (ii) Use your sketch to explain the effect of temperature on the rate of a reaction.

[2 marks] (b) 3.00 g of antimony pentachloride is vapourized. The vapour occupies a volume of 285 cm3 at standard temperature and pressure.

(i) Calculate the relative molecular mass of antimony pentachloride in the vapour state. [3 marks]

(ii) Calculate the relative molecular mass of antimony pentachloride from its

molecular formula. Explain the difference between this value and the value you obtained in (b)(i). [5 marks]

(iii) Draw the Lewis structure and state the shape of the antimony pentachloride

molecule. [2 marks]

(iv) Antimony pentaiodide does not exist. Explain why. [1 mark]

6 (a) The e.m.f. of an electrochemical cell that involves the reaction aA + bB ⇌ cC + dD is given by the equation below.

ba

dc

cellcell BA

DC

nEE

][][

][][log

059.0

with cellE as the standard cell potential and n as the number of moles of electrons transferred in

the reaction. (i) Using standard electrode potentials from the data booklet and the information

given above, calculate the equilibrium constant, Kc, for the following reaction.

Zn(s) + Cu2+(aq) ⇌ Cu(s)+ Zn2+(aq) [5 marks]

(ii) Calculate the e.m.f. of the following electrochemical cell.

Zn(s) / Zn2+(aq, 0.8 mol dm-3 ) // Cu2+(aq, 0.4 mol dm-3 ) / Cu(s) [2 marks] (b) One method of preparing sulphur dioxide in the laboratory is by mixing excess acid with an aqueous solution of sodium sulphite. Use the following data to calculate the enthalpy change of this reaction. [3 marks]

∆H/kJmol-1

H2(g) + S(s) + 2

3O2(g) → 2H+(aq) + SO3

2−(aq) − 623

S(s) + O2(g) → SO2(g) − 296

H2(g) + 2

1O2(g) → H2O(l) − 286

(c) (i) What is meant by buffer solution? [1 mark]

(ii) Explain how carbonic acid, H2CO3, and sodium hydrogen carbonate, NaHCO3, acts as a buffer in the blood. [4 marks] 962/2 *This question paper is CONFIDENTIAL until the examination is over: CONFIDENTIAL*

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7 (a) Group 2 elements form carbonates MCO3. Explain the thermal stability of the carbonates on descending the group. [5 marks] (b) Aluminium is one widely used metal in industry. Aluminium is extracted mainly from pure bauxite, Al2O3.

(i) Describe the extraction of aluminium from pure bauxite. [4 marks]

(ii) State one reason why aluminium metal is widely used in the aerospace industry.

[1 mark]

(c) When some sodium carbonate is added into aqueous aluminium sulphate solution, a colourless gas that turns lime water chalky is evolved. Explain the above observation and write all the equations involved.

[5 marks] 8 (a) Nitrogen monoxide is found in exhaust gases of motorised vehicles. A catalytic converter removes this gas from the exhaust. By using suitable chemical equations, explain the formation of nitrogen monoxide in the engine and how the gas is removed.

[3 marks] (b) No visible change is recorded when a heated glass rod is placed in a glass jar containing hydrogen chloride vapour. However, a purple vapour forms when a heated glass rod is placed in a glass jar containing hydrogen iodide vapour. Explain these observations. [3 marks] (c) A neutral, coloured compound, Q, has the empirical formula Co(Cl)x(NH3)y. The percentage by mass of cobalt, nitrogen and chlorine in the complex is as follows.

Co, 23.52% ; N, 28.00% ; Cl, 42.53% (i) Given the relative molecular mass of Q is 250.4, determine the molecular formula of Q.

[4 marks] (ii) It is found that one mole of Q reacts with two moles of silver nitrate, determine the structural formula of Q.

[1 mark] (iii) Explain why Q is coloured.

[4 marks] 962/2 *This question paper is CONFIDENTIAL until the examination is over: CONFIDENTIAL*

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9 (a) The table below shows the pKa values of several organic acids in aqueous solutions at room temperature.

Arrange these acids in order of increasing acid strength. Explain your answer.

[5 marks]

(b) Describe a chemical test to differentiate between each of the following pairs of compounds. Your answer should include reagents and conditions used, observations and chemical equations.

[6 marks]

(c) Chlorination of propane gas in the presence of ultra-violet light produces 2-chloropropane as the major product. Write a mechanism of the reaction that produces 2- chloropropane.

[4 marks] 10 (a) Paracetamol is a pain killer. The structure of paracetamol is shown below. HO— — NHCOCH3

(i) Name all the functional groups in the paracetamol molecule. [2 marks]

(ii) Paracetamol reacts with hot sodium hydroxide solution. State the type of reaction and draw the structure of the products formed.

[3 marks] (b) Write a reaction scheme to show the preparation of 3-nitrotoluene from benzene.

[4 marks]

(c) The structure below shows part of a protein molecule. —HN—CH—CO—NH—CH—CO—NH—CH2—CO— CH2 CH2

OH COOH

When the protein is hydrolysed with acid, different amino acids are formed. Two of the amino acids are optically active. Draw the structure of both the amino acids and explain why they are optically active.

[6 marks]

962/2 *This question paper is CONFIDENTIAL until the examination is over: CONFIDENTIAL*

Acid pKa Methanoic acid, HCOOH 3.80

Ethanoic acid, CH3COOH 4.80

Chloroethanoic acid, ClCH2COOH 2.90

CH3

(i)

(ii)

and

and

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[Turn over(Lihat sebelah) SULIT *

Jawapan Peperiksaan Percubaan STPM 2010 Kimia Kertas 1 1 D 11 B 21 D 31 D 41 D

2 A 12 A 22 D 32 C 42 B

3 A 13 C 23 D 33 B 43 C

4 C 14 C 24 C 34 B 44 B

5 B 15 D 25 B 35 B 45 A

6 A 16 D 26 A 36 B 46 B

7 D 17 D 27 C 37 D 47 A

8 D 18 A 28 C 38 A 48 D

9 C 19 C 29 B 39 B 49 B

10 B 20 B 30 C 40 B 50 B

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Paper 2 Answer Chemistry STPM Trial 2010

Section A 1 (a) (i) 1 (ii) 1 Bent / V-shape (iii) 1 Right shape of sp3 orbitals 1 Label sp3 hybrid orbital of S atom and 1s orbital of H atom

(b) (i) 1 O is more electronegative than S /

Bonding pair electrons in the OH bond are drawn closer to the O atom compared to the bonding pair electrons in the SH bond.

1 Repulsion between bonding pair electronbonding pair electrons in H2O in H2S 1 bond angle H-O-H > bond angle H-S-H (ii) 1 van der Waals forces between H2S molecules 1 Hydrogen bonds between H2O molecules 1 Hydrogen bonds are stronger than van der Waals forces 2 (a) (i) 1 pH is the measure of hydrogen ion concentration // pH = - log [H+] (ii) pH = - log [H+] ; 3.5 = - log [H+] 1 [H+] = 3.16 x 10-4 mol dm-3 (b) (i) HX + NaOH → NaX + H2O

1 1

1

10.05.27

0.25

x

Mx

1 M = 0.11 mol dm-3

(ii) 1 Orange juice is a weak acid. // Orange juice dissociates partially. 1 The concentration of the H+ released is not the same as the concentration of the acid in the orange

juice.

(iii) 1 cK]H[ a

1 11.0

)10x16.3(

c

]H[K

242

a

= 9.1 x 1O-7 mol dm-3

(iv) 1 Orange juice is a weak acid (pH = 3.5) and NaOH is a strong base, the pH range of phenolphthalein will enable it to produce a sharp end point.

1 Colour change is more prominent from colourless to pink 3 (a) (i) 1 Ge4+>Sn4+>Pb4+

(ii) 1 Ge2+ (iii) 1 Pb2+

1 The electrode potential for Pb4+/Pb2+ is positive, this shows that Pb4+ is readily converted to Pb2+.

(b) (i) 1 SiO2 / silica / silicon dioxide (ii) 1 Telecommunication / endoscope. (iii) 1 Optical fibres can transmit more information than copper wires. 1 Optical fibres have 100% efficiency/ no loss of signal

(c) 1 In glass, there is no regular arrangement of particles. 1 In diamond, the atoms are arranged in an orderly/ giant tetrahedral and closely-packed structure.

• • S H • •

• ×

• × H

H

S

• •••

H

sp3 hybrid orbital of S atom [1]

1s orbital of H atom [1]

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4 (a) (i) 1 Reagent: acidified potassium manganate(VII) solution 1 Equation with correct product 1 Balanced equation

H3C— —CH3 + 6[O] → HOOC— —COOH + 2H2O

(ii) 1 The methyl group is an electron releasing group 1 It activates the benzene ring

(b) (i) 1 H2N— — COOH

(ii) 1 The monomer exists as zwitterion but the polymer does not.

1 The monomer forms ion-dipole interaction / hydrogen bond with water molecules but the polymer does not.

(iii) 1 Condensation polymerization

(iv) 1 HOOC— —NH3+Cl-

Section B

5 (a) (i) 1 Labeled: y axis: fraction of particles, x axis: Ea // molecular energy 1 Correct shape of graph at 25oC and 50oC

Fraction of particles 25oC 50o C Ea Molecular energy

(ii) 1 When temperature increases the fraction of particles having energy equal to or greater than the activation energy (Ea) increases.

1 Rate increases

(b) (i) Using the ideal gas equation: pV = nRT 1 (101 X 103) (285 X 10-6) = n x 8.31 x 273 1 n = 1.27 x 10-2 mol

1 Relative molecular mass = 21027.1

00.3x

= 236.2

(ii) Antimony pentachloride is SbCl5

Relative molecular mass = (122 + 35.5(5) ) 1 = 299.5 1 The experimental relative molecular mass is less than actual relative mass

from its molecular formula. 1 SbCl5 vapour does not show ideal gas behaviour

1 Strong intermolecular forces exist between molecules 1 Volume of molecules is not negligible

(iii) 1 The Lewis diagram for the SbCl5 molecule

Cl x·

Cl x· Sb ·xCl Cl x· ·xCl http://edu.joshuatly.com/

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1 Trigonal bipyramidal (iv) 1 5 big iodine atoms cause steric hindrance

6 (a) (i) Zn(s) + Cu2+(aq) ⇌ Cu(s)+ Zn2+(aq) From data booklet:

1 Zn2+ + 2e- ⇌ Zn - 0.76 V

Cu 2+ + 2e- ⇌ Cu + 0.34 V

1 E.m.f . cell , Ecell

= + 0.34 – (- 0.76) = + 1.10 V

1 At equilibrium, Ecell = 0 V

Overall electrochemical equation is a follows.

Zn(s) + Cu2+(aq) ⇌ Zn2+(aq) + Cu(s) Ecell = +1.10 V

1 0 = 1.10 – ][

][log

2

059.02

2

Cu

Zn

1 K = 1.94 x 1037

(ii) Using ba

dc

cellcell BA

DC

nEE

][][

][][log

059.0

4.0

8.0log

2

059.010.11 cellE

09.11 cellE V

(b) 1 2H+(aq) + SO32-(aq) → H2O (l) + SO2(g) ∆H

H2(g) + S(s) + 3/2O2 → 2H+(aq) + SO32-(aq) (i) - 623

S(s) + O2(g) → SO2(g) (ii) -296 H2(g) + ½ O2 (g) → H2O (l) (iii) -286

1 (iii) + (ii) – (i) // {[H2(g) + ½ O2 (g)+ [S(s) + O2(g)] – [H2(g) + S(s) + 3/2O2]} →

{[H2O (l)] + [SO2(g)] – [2H+(aq) + SO32-(aq)]}

0 → {[H2O (l)] + [SO2(g)] – [2H+(aq) + SO32-(aq)]}

1 ∆H = (-286) + (-296) – (-623) = + 41 kJ (c) 1 A buffer solution is capable of maintaining the pH of its solution when a small amount of acid or alkali is added to it.

1 H2CO3 ⇌ H+ + HCO3-

1 NaHCO3 Na+ + HCO3-

1 When a small amount of acid is added, the hydrogen ion reacts with the HCO3- ion //

H+ + HCO3- H2CO3

1 When a small amount of alkali is added, the hydroxide ion reacts with the acid H2CO3 // OH- + H2CO3 H2O + HCO3

- 7 (a) 1 MCO3(s) → MO(s) + CO2(g)* (*Physical state is optional) 1 Thermal stability of carbonate increases as descending Group 2 1 Charge density of cation, M2+ decreases as descending Group 2 //

Ionic charge of cation remains as 2+ and the cationic size increases as descending Group 2 1 The carbonate anion, CO3

2- has relatively large electron cloud 1 Polarising power of cation, M2+ over the electron cloud of CO3

2- ion gradually weaker // Electron cloud of carbonate anion is less polarised as descending Group http://edu.joshuatly.com/

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(b) (i) 1 Electrolysis of molten bauxite with graphite anode and cathode 1 Cryolite (or) Na3AlF6; at about 950oC to 1000oC 1 Cathode: Al3+ is reduced to Al Al3+ + 3e → Al

1 Anode: O2– is oxidised to O2 2O2– → O2 + 4e

(ii) 1 Light weight and strong // resistance to corrosion (c) 1 Colourless gas is carbon dioxide. 1 Aluminium ion has high charge density. 1 The aluminium sulphate aqueous solution contains Al(H2O)6

3+ hydrated ions // Al3+(aq) + 6H2O(l) → [Al(H2O)6]

3+(aq) 1 Al(H2O)6

3+ ion hydrolyses to produce H+/ H3O+ // the salt solution is acidic //

Al(H2O)6]3+(aq) + H2O(l) → [Al(H2O)5 (OH)]2+(aq) + H3O

+ (aq)

1 2Al(H2O)63+ (aq) + 3CO3

2– (aq) → 2Al(OH)3(H2O)3(s) + 3H2O (l) + 3CO2(g)

8 (a) 1 The high temperature in the car engines N2 to combine with O2 to form NO(g). 1 N2(g) + O2(g) 2NO(g) 1 2NO + 2CO → N2 + 2CO2 // 2NO → N2 + O2 (b) 1 HCl is thermally more stable than HI 1 Purple colour = I2(g) 1 2HI → H2 + I2 (c) (i) Co : N : Cl : H

1 9.5852.23 : 0.14

00.28 : 5.3553.42 : 0.1

95.5

0.40 : 2.0 : 1.20 : 6.0 1 1 : 5 : 3 : 15

1 Empirical formula of Q = CoCl3(NH3)5 1 (CoCl3(NH3)5)n = 250 ; n =1 1 Q = [CoCl(NH3)5]

2+. 2Cl– (ii) 1 Co3+ = [Ar] 3d6, 3d orbitals are partially filled. 1 Under the influence of ligands, the 3d orbitals are split into 2 groups 1 d– d transition happens 1 Energy difference falls in the visible region 9 (a) 1 CH3COOH, HCOOH, ClCH2COOH

1 RCOOH(aq) + H2O(l) ⇌ RCOO– (aq) + H3O+(aq)

Acid Conjugate base

1 –CH3 is electron releasing group and Cl is electron withdrawing group 1     –CH3 of ethanoic acid causes O–H bond of the –COOH group to be less

polarised, thus, less able to ionise. // –CH3 of ethanoic acid destabilises the CH3COO– conjugate base and shifting the equilibrium position to the left. 1      –Cl of chloroethanoic acid causes O–H bond of the –COOH group to be

more polarised, thus more able to ionise. // –Cl of the chloroethanoic acid stabilises the CH3COO– conjugate base, thus, shifting the

equilibrium position to the right.

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(b) (i) 1 Reagent and condition: Acidified KMnO4 solution; room temperature. 1 Cyclohexene decolourises the purple colour of acidified KMnO4 solution while no obvious

observation for cyclohexane. 1 OH + (O) + H2O →

OH (ii) 1 Reagent and condition: Acidified KMnO4 solution; Heat 1 Toluene decolourises the purple colour of acidified KMnO4 solution while

no obvious observation for benzene. 1 (c) 1 Free radical substitution 1 Cl2 → 2Cl· 1 CH3CH2CH3 + Cl· → (CH3)2 CH· + HCl 1 (CH3)2 CH· + Cl2 → (CH3)2 CHCl + Cl· 10 (a) (i) 1 phenol 1 amide

(ii) 1 Alkaline hydrolysis 1 NaO— —NH2

1 CH3COONa (b)

—NO2 —NO2 50oC-60oC CH3 [1] + [1] [1] [1]

(c) H2N-*CH-COOH H2N*CHCOOH

CH2 CH2

OH COOH [1] [1]

1 Has a carbon chiral 1 shown as * in the structure 1 Mirror images are non-superimposable 1 rotates plane-polarised light

COOH + H2O

CH3Cl / FeCl3

Conc H2SO4 / Conc HNO3

CH3 + 3(O) →

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