Chemistry 2000 Paper 2+Ans

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2000-CE-CHEM 2–1

HONG KONG EXAMINATIONS AUTHORITY

HONG KONG CERTIFICATE OF EDUCATION EXAMINATION 2000

CHEMISTRY PAPER 2

10.45 am – 11.45 am (1 hour)

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, check that all the questions are there. Look forthe words ‘END OF PAPER’ after the last question.

3. ANSWER ALL QUESTIONS. All the answers should be marked on theAnswer Sheet.

4. Note that you may only mark ONE answer to each question. Two or moreanswers will score NO MARKS.

5. All questions carry equal marks. No marks will be deducted for wronganswers.

Subject Code 160

2000-CECHEM2

2000-CE-CHEM 2−2 – 1 –

There are 50 questions in this paper.

1. A compound formed from element X and sulphur has the followingelectronic structure :

(Only electrons in the outermost shells are shown.)

How many electrons are there in the outermost shell of an atom of X ?

A. 2B. 4C. 6D. 8

2. Caesium (Cs) is a Group I element in the Periodic Table and its relativeatomic mass is greater than that of potassium. Which of the followingstatements concerning caesium is INCORRECT ?

A. Caesium is a weaker reducing agent than potassium.B. Caesium reacts violently with water.C. Caesium is a soft metal.D. Caesium reacts with oxygen to form an oxide with

formula Cs2O.

3. Iron cans used for canning food are usually coated with tin instead of zinc.This is because

A. tin is more reactive than zinc.B. tin ions are non-toxic but zinc ions are toxic.C. tin forms an alloy with iron and this alloy is corrosion

resistant.D. tin prevents iron cans from rusting by sacrificial

protection.

SS X

保留版權 All Rights Reserved 2000

2000-CE-CHEM 2–3 – 2 – Go on to the next page

4. Metal X forms an oxide. 27.53 g of this oxide contains 24.96 g of X. Whatis the mole ratio of X to oxygen in the oxide ?

(Relative atomic masses : O = 16.0, X = 207.0)

A. 1 : 1B. 1 : 2C. 2 : 3D. 3 : 4

5. Which of the following gases are the major products liberated in theelectrolysis of concentrated sodium chloride solution using carbonelectrodes ?

Cathode Anode

A. hydrogen chlorineB. chlorine hydrogenC. hydrogen oxygenD. oxygen hydrogen

6. Which of the following pairs of compounds can be distinguished by treatingwith an acidified potassium dichromate solution ?

A. ethane and etheneB. ethanol and propan-1-olC. sodium carbonate and sodium hydrogencarbonateD. sodium sulphite and sodium sulphate

7. Element X occurs in nature as two isotopes, 63X and 65X. If the relativeatomic mass of X is 63.5, what is the relative abundance of the 63X isotope ?

A. 25%B. 60%C. 75%D. 90%


2000-CE-CHEM 2−4 – 3 –

8. Which of the following statements concerning members of a homologousseries is INCORRECT ?

A. They contain carbon and hydrogen only.B. They can be represented by the same general formula.C. They have similar chemical properties.D. Their boiling points increase with their relative molecular

masses.

9. The atomic number of element X is 12. X reacts with element Y to forman ionic compound with formula XY2. To which group of the PeriodicTable does Y belong ?

A. Group IB. Group IVC. Group VID. Group VII

10. Manufacturing ammonia by the Haber process involves the reversiblereaction :

N2(g) + 3H2(g) 2NH3(g)

Which of the following statements concerning the process isINCORRECT ?

A. The forward reaction can go to completion if iron powderis used as a catalyst.

B. The optimum conditions for the process are 500°C and200 atm.

C. The raw materials are derived from air and water.D. The forward reaction and backward reaction occur

simultaneously.


2000-CE-CHEM 2−5 – 4 – Go on to the next page

11. Different volumes of 2.0 M potassium hydroxide solution and 2.0 Msulphuric acid are mixed in a polystyrene cup. In which of the followingcombinations would the temperature rise be the greatest ?

3KOH(aq)/cmM0.2ofVolume 342 (aq)/cmSOHM0.2ofVolume

A. 20.0 40.0B. 30.0 30.0C. 40.0 20.0D. 45.0 15.0

12. Which of the following natural substances is essentially a singlecompound ?

A. airB. coalC. petroleumD. quartz

13. Consider the compounds represented by the two structures below :

Which of the following statements concerning these compounds is correct ?

A. Both compounds can turn wet blue litmus paper red.B. Both compounds have the same odour.C. Both compounds have the same molecular formula.D. Both compounds have the same boiling point.

H C

O

O C

H

H

C

H

H

H H C

H

H

C

H

H

C

O

O Hand


2000-CE-CHEM 2−6 – 5 –

14. Which of the following solutions can react with bromine water to give acolourless solution ?

A. sodium chloride solutionB. sodium sulphite solutionC. sodium iodide solutionD. sodium hypochlorite solution

15. A polymer has the following structure :

What is the monomer of this polymer ?

A. butaneB. but-1-eneC. but-2-eneD. 2-methylpropene

16. Consider the following equation :

3Zn(s) + 2NO3–(aq) + 8H+(aq) → 3Zn2+(x) + 2NO(y) + 4H2O(z)

Which of the following combinations is correct ?

x y zA. aq g aqB. aq gC. aq aqD. g aq

17. The melting point and boiling point of substance X are 321°C and 765°Crespectively. In its molten state, X conducts electricity withoutdecomposition. X probably has

A. an ionic structure.B. a metallic structure.C. a simple molecular structure.D. a covalent network structure.

C C

CH3

H H

CH3

n



18. Some potassium carbonate solution is added to a sample of tap water. Themixture then appears cloudy. Which of the following ions is probablypresent in the sample ?

A. NH4+

B. Mg2+

C. Br–

D. SO42–

19. Gold ornaments are usually made from an alloy of gold and copper insteadof pure gold. This is because the alloy

A. can be found free in nature.B. is more corrosion resistant than pure gold.C. is denser than pure gold.D. is stronger than pure gold.

20. A sample of concentrated sulphuric acid has a density of 1.83 g cm–3 andcontains 94.0% of sulphuric acid by mass. What is the concentration(correct to one decimal place) of sulphuric acid in the sample ?

(Relative atomic masses : H = 1.0, O = 16.0, S = 32.1)

A. 17.5 MB. 18.3 MC. 18.7 MD. 19.8 M

21. Which of the following processes requires a catalyst ?

A. preparation of ethyl ethanoate from ethanoic acid andethanol

B. conversion of sulphur trioxide to concentrated sulphuricacid

C. manufacture of chlorine bleach from brineD. reduction of iron(III) oxide to iron


2000-CE-CHEM 2−8 – 7 –

22. A white solid dissolves in water to give an alkaline solution. The solutionreacts with dilute hydrochloric acid to give a gas. The solid is probably

A. calcium oxide.B. calcium carbonate.C. potassium hydroxide.D. potassium carbonate.

23. In an experiment, 21.8 g of zinc was treated with 250.0 cm3 o f 2.0 Mhydrochloric acid. What volume of hydrogen was liberated at roomtemperature and pressure ?

(Relative atomic mass : Zn = 65.4; molar volume of gas at room temperature and pressure = 24.0 dm3)

A. 4.0 dm3

B. 6.0 dm3

C. 8.0 dm3

D. 12.0 d m3

24. Which of the following compounds is insoluble in water ?

A. methanolB. methanoic acidC. methyl methanoateD. sodium methanoate

(This item was deleted.)

25. Which of the following processes is endothermic ?

A. cracking of petroleum fractionsB. fermentation of glucose solutionC. manufacture of ammonia by the Haber processD. oxidation of sulphur dioxide to sulphur trioxide in the

contact process



26. Which of the following combinations is correct ?

fireofType usetoerextinguishfireofType

A. electrical fire water B. electrical fire foamC. kerosene fire waterD. kerosene fire foam

27. Which of the following changes occurs in a catalytic converter installed in amotor car ?

A. Nitrogen monoxide changes to nitrogen dioxide.B. Carbon monoxide changes to carbon dioxide.C. Unburnt hydrocarbons change to carbon particles.D. Sulphur changes to sulphur dioxide.

28. Which of the following changes is NOT a redox reaction ?

A. Fe2(SO4)3 + H2S → 2FeSO4 + S + H2SO4

B. 2Al + 6HCl → 2AlCl3 + 3H2

C. CaCO3 + CO2 + H2O → Ca(HCO3)2

D. 2KClO3 → 2KCl + 3O2

29. Which of the following compounds would react with ammonium chlorideon heating ?

A. concentrated nitric acidB. concentrated hydrochloric acidC. sodium hydroxide solutionD. magnesium sulphate solution


2000-CE-CHEM 2−10 – 9 –

30. In which of the following substances does nitrogen has the smallestoxidation number ?

A. NH3B. NOC. N2OD. N2

31. Which of the following uses of sulphuric acid is/are correct ?

(1) manufacture of soaps(2) manufacture of paint additives(3) manufacture of fertilizers

A. (1) onlyB. (2) onlyC. (1) and (3) onlyD. (2) and (3) only

32. Which of the following articles should be made from thermosettingplastics ?

(1) wall paper(2) television casing(3) water bucket


33. In an experiment, a piece of calcium metal was added to a beaker of water.Which of the following statements concerning the experiment is/arecorrect ?

(1) The calcium metal sank to the bottom of the beaker.(2) The calcium metal burnt with a brick red flame.(3) At the end of the experiment, an alkaline solution was formed in

the beaker.




34. Which of the following statements concerning helium is/are correct ?

(1) The outermost electron shell of a helium atom has an octetstructure.

(2) Helium is used to fill weather balloons.(3) Helium exists as monatomic molecules.


35. Consider the chemical cell shown below :

Which of the following statements concerning the cell is/are correct ?

(1) Oxidation takes place at the copper electrode.(2) The concentration of magnesium ions in beaker X increases.(3) The salt bridge allows electrons to flow from one electrode to the

other electrode.


magnesium copper

1M copper(II)sulphate solution

1M magnesium sulphate solution

Beaker X Beaker Y

salt bridge


2000-CE-CHEM 2−12 – 11 –

36. Which of the following polymers is/are made by condensationpolymerization ?


37. Which of the following statements concerning drugs is/are correct ?

(1) Morphine is an effective painkiller.(2) Acetaminophen (paracetamol) can damage the stomach lining.(3) A suspension of milk of magnesia in water has a pH greater than 7.


CH2 C

CH3

C OCH3

O

C (CH2)4 C N (CH2)6 N

O O H H

n

n(2)

(1)

C

F

F

C

F

Fn

(3)



38.

Some concentrated sulphuric acid was poured into a sink connected to acatchpot made of polyvinyl chloride (PVC). After some time, the catchpotbecame deformed. Which of the following explanations for thedeformation of the catchpot is/are correct ?

(1) The heat liberated when the concentrated sulphuric acid mixed withthe water in the catchpot caused PVC to soften.

(2) PVC was decomposed into its monomers by the concentratedsulphuric acid.

(3) PVC was oxidized by the concentrated sulphuric acid.


sink

catchpot


2000-CE-CHEM 2−14 – 13 –

39. X is an element in Group VI of the Periodic Table. X can form X2– ions.Which of the following statements are correct ?

(1) The oxidation number of X decreases when X2– ion is formed.(2) Both X atom and X2– ion have the same number of electron shells.(3) Both X atom and X2– ion have the same nuclear charge.

A. (1) and (2) onlyB. (1) and (3) onlyC. (2) and (3) onlyD. (1), (2) and (3)

40. Which of the following measures can reduce the emission of pollutants froma coal-fired power station ?

(1) installation of scrubbers(2) installation of electrostatic precipitators(3) increasing the height of the chimney


41. Which of the following statements concerning soaps are correct ?

(1) They are esters.(2) They can reduce the surface tension of water.(3) Their aqueous solutions are alkaline.




42. Which of the following statements concerning carbon, silicon andphosphorus are correct ?

(1) Carbon forms numerous compounds with hydrogen and oxygen.(2) Silicon is used to make computer chips.(3) Phosphorus is an essential element for plant growth.


43. Which of the following statements concerning a zinc-carbon cell are correct ?

(1) The ammonium chloride in the cell acts as an electrolyte.(2) The manganese(IV) oxide in the cell acts as an oxidizing agent.(3) The zinc case of the cell acts as the positive terminal.


44. Which of the following statements concerning sulphur dioxide are correct ?

(1) It can be prepared by heating copper turnings with concentratedsulphuric acid.

(2) It is denser than air.(3) It can be absorbed by sodium hydroxide solution.



2000-CE-CHEM 2−16 – 15 –

Directions : Each question below (Question Nos. 45 to 50) consists of twoseparate statements. Decide whether each of the two statements istrue or false; if both are true, then decide whether or not the secondstatement is a correct explanation of the first statement. Then selectone option from A to D according to the following table :

A. Both statements are true and the 2nd statement is a correct explanation of the1st statement.

B. Both statements are true but the 2nd statement is NOT a correct explanation ofthe 1st statement.

C. The 1st statement is false but the 2nd statement is true.D. Both statements are false.

1st statement 2nd statement

45. Concentrated sulphuric acid canturn a piece of filter paper black.

Concentrated sulphuric acid is astrong oxidizing agent.

46. Carbon dioxide and silicon dioxidehave similar physical properties.

The atoms of carbon and siliconhave the same number of electronsin their outermost shells.

47. Chlorine is a better bleaching agentfor silk than sulphur dioxide.

Chlorine bleaches by reduction.

48. The volume of 10.0 g of gaseouscarbon dioxide is the same as thevolume of 10.0 g of solid carbondioxide.

10.0 g of gaseous carbon dioxidecontains the same number ofmolecules as 10.0 g of solid carbondioxide.

49. Adding lime to acidic soil canincrease crop yield.

Lime can neutralize the acid in thesoil.

50. Aluminium was used earlier thaniron in the history of mankind.

Aluminium is more abundant thaniron in the earth crust.

END OF PAPER


2000 Chemistry Paper 2

Question No. Key Question No. Key 1. B 26. D 2. A 27. B 3. B 28. C 4. D 29. C 5. A 30. A

6. D 31. D 7. C 32. B 8. A 33. C 9. D 34. D 10. A 35. B

11. C 36. A 12. D 37. C 13. C 38. A 14. B 39. D 15. C 40. A

16. B 41. C 17. B 42. D 18. B 43. A 19. D 44. D 20. A 45. B

21. A 46. C 22. D 47. D 23. B 48. C 24. 49. A

25. A 50. C


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Chemistry 2000 Paper 2+Ans