Chemistry 2002 Paper 2+ans

2002-CE CHEM 2

HONG KONG EXAMINATIONS AUTHORITY HONG KONG CERTIFICATE OF EDUCATION EXAMINATION 2002

CHEMISTRY PAPER 2 10.45 am – 11.45 am (1 hour)

Subject Code 160

1.

Read carefully the instructions on the Answer Sheet and insert the information required (including the Subject Code) in the spaces provided.

2.

When told to open this book, you should check that all the questions are there. Look for the words ‘END OF PAPER’ after the last question.

3.

All questions carry equal marks.

4.

ANSWER ALL QUESTIONS. You should mark all your answers on the Answer Sheet.

5.

You should mark only ONE answer for each question. If you mark more than one answer, you will receive NO MARKS for that question.

6.

No marks will be deducted for wrong answers.

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2002-CE-CHEM 2–1

There are 50 questions in this paper. Choose the best answer for each question. 1.

The electronic diagram of an atom of element X is shown below :

X (Only electrons in the outermost shell are shown.) The atomic number of X is probably A. B. C. D. 2.

Which of the following compounds, when dissolved in water, gives a green solution ? A. B. C. D.

3.

7. 15. 17. 19.

copper(II) sulphate nickel(II) sulphate cobalt(II) chloride iron(III) sulphate

An oxide of element X has the formula X2O3. 10.2 g of this oxide contains 5.4 g of X. What is the relative atomic mass of X ? (Relative atomic mass : O = 16.0) A. B. C. D.

4.

12.0 18.0 27.0 36.0

Which of the following statements concerning drugs is INCORRECT ? A. B. C. D.

Acetylsalicylate can cause addiction. Magnesium hydroxide can reduce stomach disturbance. Codeine can alleviate coughing. Morphine can relieve pain.

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5.

Consider the aqueous solutions listed below : (1) (2) (3)

1M ethanoic acid 1M hydrochloric acid 1M ammonia solution

Which of the following represents the increasing order of pH of the solutions ? A. B. C. D. 6.

Compound X dissolves in water to give a colourless solution. When chlorine gas is bubbled into the solution, the solution turns brown. X is probably A. B. C. D.

7.

(1), (2), (3) (2), (1), (3) (3), (1), (2) (3), (2), (1)

ammonium iodide. iron(II) sulphate. sodium sulphite. potassium hydroxide.

Sodium chromate, Na2CrO4 , dissolves in water to give a yellow solution. When dilute hydrochloric acid is added to the solution, the following reaction occurs : 2CrO42–(aq) + 2H+(aq) → Cr2O72–(aq) + H2O(l) Which of the following statements concerning this reaction is correct ? A. B. C. D.

The colour of the solution changes from yellow to green. Chromate ions act as a reducing agent. The oxidation number of oxygen remains unchanged during the reaction. The reaction is a neutralization.

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8.

Which of the following statements concerning aluminium is correct ? A. B.

Aluminium is used to make stainless steel. The strength of aluminium can be enhanced by anodization. Aluminium is the most abundant element in the earth’s crust. When aluminium is exposed to air, a layer of aluminium oxide is formed on its surface.

C. D.

9.

Which of the following equations represents a cracking reaction ? C4H8 + H2 → C4H10 C4H10 → C3H6 + CH4 C6H12O6 → 2C2H5OH + 2CO2 C4H9OH → C4H8 + H2O

A. B. C. D. 10.

Consider the set-up shown below :

V

electron flow

salt bridge X

Y

zinc sulphate solution

Z

Electrons flow from X to Y in the external circuit. Which of the following combinations is correct ?

A. B. C. D.

X

Y

carbon zinc carbon zinc

silver magnesium carbon carbon

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Z silver nitrate solution magnesium sulphate solution copper(II) sulphate solution silver nitrate solution

11.

Which of the following petroleum fractions has a supply that outweighs the demand in modern society ? A. B. C. D.

12.

Which of the following reactions does NOT require the use of a catalyst ? A. B. C. D.

13.

conversion of ammonia to nitrogen monoxide hydration of ethene to give ethanol oxidation of ethanol to ethanoic acid fermentation of glucose to give ethanol

Which of the following equations represents a redox reaction ? A. B. C. D.

14.

fuel gases kerosene petrol heavy oil

Ca(HCO3)2 + 2HCl → CaCl2 + 2CO2 + 2H2O PCl3 + Cl2 → PCl5 Fe3+ + 3OH– → Fe(OH)3 Al2O3 + 2NaOH → 2NaAlO2 + H2O

Ammonium dichromate, (NH4)2Cr2O7 , decomposes on heating to give chromium(III) oxide, water and nitrogen. What mass of water is obtained when 126 g of ammonium dichromate undergoes complete decomposition ? (Relative atomic masses : H = 1.0, N = 14.0, O = 16.0, Cr = 52.0) A. B. C. D.

9g 18 g 36 g 72 g

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15.

Which of the following combinations concerning the functions of food additives is correct ? Food additive A. B. C. D.

16.

sulphur dioxide in wine sodium chloride in potato chips sodium benzoate in oyster sauce monosodium glutamate in instant noodles

Function flavour enhancer flavouring colouring antioxidant

Gases X and Y react to give a gaseous product Z. The reaction can be represented by the equation : X(g) + 3Y(g) → 2Z(g) In an experiment, 40 cm3 of X and 60 cm3 of Y are mixed and are allowed to react in a closed vessel. What is the volume of the resultant gaseous mixture ? (All volumes are measured at room temperature and pressure.) A. B. C. D.

17.

Which of the following solutions does NOT react with sodium hydroxide solution ? A. B. C. D.

18.

40 cm3 60 cm3 80 cm3 100 cm3

ammonium chloride solution potassium carbonate solution copper(II) nitrate solution zinc sulphate solution

The symbol of vanadium is V. What is the oxidation number of vanadium in NH4VO3 ? A. B. C. D.

–1 +3 +5 +6

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19.

Which of the following acids, when heated with copper, would produce a gas ? A. B. C. D.

20.

dilute nitric acid dilute hydrochloric acid dilute sulphuric acid concentrated ethanoic acid

The monomer of polymer X is chloroethene. statements concerning X is correct ? A. B. C. D.

Which of the following

X is a condensation polymer. X is a thermosetting plastic. X is used in making drainage pipes. The repeating unit of X is as follows : Cl Cl

21.

C

H

H

In a boiler using hard water, scale is deposited on its interior after a period of time. The scale consists mainly of metal carbonates. Which of the following substances can be used to remove the boiler scale ? A. B. C. D.

22.

C

soapless detergent chlorine bleach sodium hydroxide solution vinegar

Which of the following methods should be used to obtain hydrated copper(II) sulphate from copper(II) sulphate solution ? A. B. C. D.

crystallization distillation fractional distillation heating under reflux

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23.

Which of the following gases contains the greatest number of molecules at room temperature and pressure ? (Relative atomic masses : H = 1.0, A. B. C. D.

24.

It is manufactured by treating sodium with water. Its concentrated solution is corrosive. It is used in the manufacture of soapless detergents. It absorbs carbon dioxide when exposed to air.

Which of the following statements concerning the Haber process is INCORRECT ? A. B. C. D.

26.

2.0 g of hydrogen 16.0 g of oxygen 18.0 g of ammonia 60.0 g of chlorine

Which of the following statements concerning sodium hydroxide is INCORRECT ? A. B. C. D.

25.

N = 14.0, O = 16.0, Cl = 35.5)

Nitrogen and hydrogen undergo complete reaction in the reaction chamber. Nitrogen and hydrogen are compressed to about 200 atm before they are allowed to undergo reaction. The process is operated at about 500°C. The reaction between nitrogen and hydrogen is exothermic.

When a piece of copper is dropped into an aqueous solution of compound X, the copper gradually dissolves. X is probably A. B. C. D.

magnesium chloride. lead(II) nitrate. silver nitrate. ammonium chloride.

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27.

Which of the following objects is least likely to contain titanium ? A. B. C. D.

28.

Which of the following substances does not conduct electricity in its solid state but does conduct electricity in its liquid state ? A. B. C. D.

29.

lithium chloride phosphorus platinum perspex

In which of the following substances are the molecules furthest apart from each other at room temperature and pressure ? A. B. C. D.

30.

missile water tap bicycle frame artificial hip joint

butane water propan-1-ol iodine

Starch, a natural polymer, is a carbohydrate. When concentrated sulphuric acid is added dropwise to some starch, a black substance is formed. The reaction involved is A. B. C. D.

dehydration. depolymerization. redox reaction. neutralization.

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31.

A part of the flow diagram for the Contact process is shown below : Y SO2 reaction chamber

absorption tower

Z

X Which of the following combinations is correct ?

A. B. C. D. 32.

X

Y

Z

air air oxygen oxygen

water concentrated sulphuric acid sulphur trioxide water

concentrated sulphuric acid oleum concentrated sulphuric acid oleum

A black powder is suspected to be carbon or a mixture of carbon and copper(II) oxide. Which of the following methods can be used to identify the black powder ? (1) (2) (3)

adding dilute sulphuric acid to the powder adding sodium hydroxide solution to the powder heating the powder strongly A. B. C. D.

33.

(1) only (2) only (1) and (3) only (2) and (3) only

Which of the following reactions is/are endothermic ? (1) (2) (3)

the fermentation of glucose the cracking of naphtha the reaction of lime with dilute hydrochloric acid A. B. C. D.

(1) only (2) only (1) and (3) only (2) and (3) only

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34.

Upon complete combustion, gaseous hydrocarbon X gives an equal number of moles of carbon dioxide and water. Which of the following hydrocarbons may X be ? (1) (2) (3)

ethane ethene propene A. B. C. D.

35.

A student heated a mixture of fat and sodium hydroxide solution for some time. He then added the mixture to a beaker of saturated sodium chloride solution. A white solid was formed. Which of the following statements concerning this experiment is/are correct ? (1) (2) (3)

The reaction between fat and sodium hydroxide is esterification. The white solid is a soap. The white solid contains salts of alkanoic acids. A. B. C. D.

36.

(1) only (2) only (1) and (3) only (2) and (3) only

(1) only (2) only (1) and (3) only (2) and (3) only

Which of the following statements concerning fluorine is/are correct ? (1) (2) (3)

It exists as monatomic molecules. It reacts with hydrogen to form a covalent compound. It reacts with calcium to form a compound with the formula CaF2. A. B. C. D.

(1) only (2) only (1) and (3) only (2) and (3) only

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37.

Which of the following methods can be used to distinguish between iron(II) sulphate solution and iron(III) sulphate solution ? (1) (2) (3)

observing their colours adding acidified potassium permanganate solution adding aqueous ammonia A. B. C. D.

38.

(1) and (2) only (1) and (3) only (2) and (3) only (1) , (2) and (3)

Which of the following set-ups can be used to dry moist sulphur dioxide gas ? (1)

(2) gas

anhydrous calcium chloride gas

calcium oxide (3)

gas

concentrated sulphuric acid A. B. C. D.

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

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39.

Which of the following statements concerning Group VII elements and their ions are correct ? (1) (2) (3)

Chlorine has the highest oxidizing power among chlorine, bromine and iodine. Iodide ions have the highest reducing power among chloride, bromide and iodide ions. Bromine is a volatile liquid at room temperature and pressure. A. B. C. D.

40.

Which of the following gases can cause global warming ? (1) (2) (3)

methane carbon dioxide chlorofluorocarbons A. B. C. D.

41.

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

When sulphur dioxide is bubbled into water, a colourless solution is formed. Which of the following statements concerning the solution are correct ? (1) (2) (3)

The solution conducts electricity better than water. The solution can change iron(III) sulphate solution from yellow to green. The solution can change potassium bromide solution from colourless to brown. A. B. C. D.

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

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42.

In which of the following is ammonia used ? (1) (2) (3)

the manufacture of nitric acid the making of fertilizers the making of antiacids A. B. C. D.

43.

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

In which of the following processes will carbon dioxide be produced ? (1) (2) (3)

the fermentation of glucose solution the biodegradation of animal faeces the treatment of car exhaust in a catalytic converter A. B. C. D.

44.

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

Both ethene and ethyne are gaseous hydrocarbons. Their structures are shown below : H

H C

C

H

H

C

C

H

H ethene

ethyne

Which of the following statements concerning ethene and ethyne are correct ? (1) (2) (3)

Both are unsaturated hydrocarbons. Both are insoluble in water. Ethyne burns with a more sooty flame than ethene. A. B. C. D.

(1) and (2) only (1) and (3) only (2) and (3) only (1), (2) and (3)

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Directions : Each question below (Question Nos. 45 to 50) consists of two separate statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table : A. Both statements are true and the 2nd statement is a correct explanation of the 1st statement. B. Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement. C. The 1st statement is false but the 2nd statement is true. D. Both statements are false. 1st statement

2nd statement

45. Nitrogen monoxide is a gas at room temperature and pressure.

Nitrogen monoxide is a covalent compound.

46. Combustion of diamond gives carbon dioxide.

Diamond is a crystalline form of carbon.

47. During electrolysis, oxidation takes place at the cathode.

Cations accept electrons and are discharged at the cathode.

48. The basicity of methanoic acid is different from that of ethanoic acid.

The number of hydrogen atoms in a molecule of methanoic acid is different from that in a molecule of ethanoic acid.

49. When iodine sublimes, it absorbs energy.

Energy is required to overcome the attractive force between iodine molecules.

50. A foam extinguisher is suitable for putting out electrical fires.

The foam from a foam extinguisher is an electrical insulator.

END OF PAPER

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2002 Chemistry Paper 2 Question No.

Key

Question No.

Key

1. 2. 3. 4. 5.

C (86) B (46) C (68) A (63) B (72)

26. 27. 28. 29. 30.

C (66) B (55) A (77) A (41) A (81)

6. 7. 8. 9. 10.

A (74) C (47) D (74) B (86) D (44)

31. 32. 33. 34. 35.

B (47) C (42) B (64) D (59) D (32)

11. 12. 13. 14. 15.

D (60) C (29) B (50) C (64) B (72)

36. 37. 38. 39. 40.

D (65) D (29) B (31) D (36) D (28)

16. 17. 18. 19. 20.

B (25) B (52) C (66) A (52) C (59)

41. 42. 43. 44. 45.

A (34) A (61) D (57) D (35) B (69)

21. 22. 23. 24. 25.

D (38) A (69) C (56) A (28) A (64)

46. 47. 48. 49. 50.

A (42) C (60) C (46) A (63) D (66)

Note: Figures in brackets indicate the percentages of candidates choosing the correct answers.

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