Chemistry Sample Draft

Draft as of December 2008

HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITY

HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION

CHEMISTRY PAPER 1

( S a m p l e P a p e r )

Time allowed: 2 hours 30 minutes

This paper must be answered in English.

GENERAL INSTRUCTIONS

1. There are TWO sections, A and B, in this Paper. Section A carries 36 marks and Section B carries 84 marks. You are advised to finish Section A in about 45 minutes and Section B in about 105 minutes.

2. Section A consists of multiple-choice questions in this question book, while Section B contains conventional questions printed separately in Question-Answer Book B.

3. Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to Section B should be written in the spaces provided in Question-Answer Book B. The Answer Sheet for Section A and the Question-Answer Book for Section B must be handed in separately at the end of the examination.

SECTION A (MULTIPLE-CHOICE QUESTIONS) INSTRUCTIONS FOR SECTION A

1. Read the instructions on the Answer Sheet carefully. Stick a barcode label and insert the information required 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 SECTION A after the last question.

3. All questions carry equal marks.

4. ANSWER ALL QUESTIONS. You should use an HB pencil to mark all your answers on the Answer Sheet. Wrong marks must be completely erased.

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.

Hong Kong Examinations and Assessment Authority All Rights Reserved 2008

Not to be taken away before the end of the examination session

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This section consists of two parts. There are 24 questions in PART I and 12 questions in PART II.

Choose the best answer for each question.

Candidates may refer to the Periodic Table printed on the back of this Question Book.

PART I

1. Upon cracking, one molecule of decane (C10H22) gives two molecules of propene and one molecule of an alkane ( X ). What is X ?

A. C4H6 B. C4H10 C. C7H14 D. C7H16

2. In which of the following compounds does sulphur exhibit the lowest oxidation number ?

A. Na2S2O3 B. MgSO4 C. KHSO3 D. H2S2O7

3. Which of the following correctly describes the sequence of procedures to separate sand, salt and water from a mixture of sand and salt solution ?

A. filtration, evaporation B. filtration, distillation C. crystallisation, filtration D. crystallisation, filtration, distillation

4. The structure of polymer X is shown below.

H CH3 H CH3 H CH3

. . . . . .C C C C C C

H CH3 H CH3 H CH3

What is the monomer of X ?

A. 1,1-dimethylethene B. 1,2-dimethylethene

C. methylpropene D. but-1-ene

2

CORROSIVE OXIDISING


Directions: Questions 5 to 6 refer to the following experiment.

Rust indicator containing potassium hexacyanoferrate(III) solution was poured into the following glass dishes to cover the iron nails, which were wrapped with different metal strips. The dishes were allowed to stand in air for some time.

silver strip zinc strip copper strip magnesium strip dish 1 dish 2 dish 3 dish 4

5. If the iron nail rusts, what would the colour of the rust indicator be around the nail ?

A. yellow B. brown C. red

D. blue

6. In which of the dishes would the iron nail rust ?

A. dish 1 only B. dish 2 only C. dish 1 and dish 3 only D. dish 2 and dish 4 only

7. The atomic number of an element X is 18. An atom of X has a mass number of 40. The atom has

A. 18 protons, 22 neutrons and 18 electrons. B. 18 protons, 22 neutrons and 22 electrons. C. 18 protons, 40 neutrons and 18 electrons. D. 22 protons, 22 neutrons and 18 electrons.

8. The following hazard warning labels are displayed on the reagent bottle of an acid.

What information about this acid can be obtained from the labels ?

A. It is very concentrated and flammable. B. It is very concentrated and oxidising. C. It is flammable and corrosive. D. It is corrosive and oxidising.

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9. Which of the following statements concerning alkenes is INCORRECT ?

A. They can decolourise a solution of bromine. B. They can decolourise red litmus solution. C. They can decolourise acidified potassium permanganate solution. D. They can be polymerised to form addition polymers.

10. Which of the following reactions is endothermic ?

A. Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s) B. CaCO3(s) + 2H+(aq) Ca2+(aq) + H2O(l) + CO2(g)

C. 2C4H10(g) + 13O2(g) 8CO2(g) + 10H2O(l) D. C9H20(l) C2H6(g) + C3H6(g) + C4H8(g)

11. Element X has three isotopes, 206X, 207X and 208X. The graph below shows the relative abundances of the isotopes.

70

60

50

40

30

20

10

0 206 207 208

What is the relative atomic mass of X ?

A. 206.8 B. 207.0 C. 207.3

D. 207.5

rela

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abun

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12. Which of the following combinations concerning the set-up shown below is correct after a current has flowed through the external circuit for some time ?

V

copper rod silver rod

copper(II) sulphate solution

Mass of anode Colour of copper(II) sulphate solution

A. increases no change B. decreases no change C. increases becomes lighter D. decreases becomes lighter

13. Standard enthalpy changes of several reactions, as denoted by x, y and z respectively, are listed in the table below.

Reaction Standard enthalpy change / kJ mol1

C(s) + O2(g) CO2(g) x H2(g) + 2

1 O2(g) H2O(l) y C(s) + 2H2(g) CH4(g) z

For the reaction CH4(g) + 2O2(g) CO2(g) + 2H2O(l), which of the following is a reasonable estimate of its standard enthalpy change ?

A. x + y z B. x y + z C. x + 2y z D. x 2y z

14. 500 cm3 of calcium hydroxide solution contains 3.7 g of calcium hydroxide. What is the molarity of the solution ?

(Relative atomic masses : H = 1.0, O = 16.0, Ca = 40.1)

A. 0.05 M B. 0.10 M C. 0.13 M

D. 0.26 M

15. Which of the following samples of gases contains the smallest number of molecules ?

(Relative atomic masses : H = 1.0, C = 12.0, N = 14.0, O = 16.0, S = 32.1)

A. 10 g of NO2 B. 10 g of CO2 C. 10 g of H2S D. 10 g of C2H4



Directions: Questions 16 to 18 refer to the following information.

In an experiment to determine the concentration of sulphuric acid in a brand of toilet cleaner, 25.0 cm3 of the cleaner was first diluted to 250.0 cm3 with distilled water. Upon titration with 0.950 M sodium hydroxide solution using phenolphthalein as indicator, 25.0 cm3 of the diluted cleaner required 27.1 cm3 of the sodium hydroxide solution to reach the end point.

16. Which of the following types of apparatus should be used to measure 25.0 cm3 of the toilet cleaner ?

A. pipette B. burette

C. measuring cylinder D. volumetric flask

17. What is the colour change at the end point of the titration ?

A. from colourless to pink B. from pink to colourless C. from yellow to red D. from red to yellow

18. What is the concentration of sulphuric acid in the undiluted toilet cleaner ?

A. 1.29 M B. 2.58 M C. 5.15 M

D. 10.3 M

19. In an experiment, 10.0 g of KCl(s) was added to 100 cm3 of water. The mixture was then stirred until all the KCl(s) dissolved. The temperature of the mixture was found to drop by 5.5C. What is the molar enthalpy change, in kJ mol1, of the dissolving process of KCl(s) under the conditions of the experiment ?

(Specific heat capacity of the mixture = 4.2 J g1 K1 ; Density of water = 1.0 g cm3 ;

Relative atomic masses: K = 39.1, Cl = 35.5)

A. 2.31 B. 2.54 C. 17.23

D. 18.96

20. 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) adding dilute sulphuric acid to the powder (2) adding sodium hydroxide solution to the powder (3) heating the powder strongly

A. (1) only B. (2) only

C. (1) and (3) only D. (2) and (3) only

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21. Consider the following experiment :

carbon electrode Y carbon electrode X

dilute hydrochloric acid dilute hydrochloric acid

gel containing copper(II) dichromate

Which of the following statements concerning the experiment are correct ?

(1) Gas bubbles are evolved at electrode X. (2) An orange colour gradually appears in the solution around electrode Y. (3) The experiment can be used to show that ions migrate towards oppositely charged electrodes.

A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only

D. (1), (2) and (3)

22. Iodine is a solid at room temperature and pressure. Which of the following statements concerning the structure of iodine is/are correct ?

(1) Iodine has a giant covalent structure. (2) Iodine molecules are held together by van der Waals forces. (3) Iodine atoms are held together in pairs by covalent bonds.



Directions : Each question below (Questions 23 to 24) 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

23. Bromine water can be used to distinguish Bromine can be reduced by sodium sulphite to between sodium sulphate solution and sodium colourless bromide ions, but not by sodium sulphite solution. sulphate.

24. Carbon dioxide and silicon dioxide have similar The atoms of carbon and silicon have the same physical properties. number of electrons in their outermost shells.

END OF PART I



PART II

25. Which of the following changes will NOT increase the initial rate of the reaction between 50 cm3 of 1 M HCl(aq) and excess calcium carbonate granules ?

A. using 100 cm3 of HCl(aq) instead of 50 cm3 of HCl(aq) B. using 2 M HCl(aq) instead of 1 M HCl(aq)

C. using 25 cm3 of 2 M HCl(aq) instead of 50 cm3 of 1 M HCl(aq) D. using calcium carbonate powder instead of calcium carbonate granules

26. Which of the following conversions is a substitution reaction ?

A. CH3CH2CH=CH2 CH3CH2CHBrCH3 B. CH3CH2CH2CH2OH CH3CH2CH2CHO C. CH3CH2CHOHCH3 CH3CH2CHBrCH3

D. CH3CH2CH2CO2H CH3CH2CH2CH2OH

27. A compound with an ester functional group has a molecular formula of C4H8O2 . What is the number of possible structures of the compound ?

A. 3 B. 4

C. 5 D. 6

28. Which type of reaction is involved in converting propan-2-ol to propene ?

A. addition B. oxidation

C. dehydration D. substitution

29. Consider the following system at equilibrium :

A(g) + 2B(g) 2C(g) H = +200 kJ mol-1

What would be the effect on the rates of the forward and backward reactions if the temperature of the system were lowered ?

forward reaction rate backward reaction rate

A. decreases increases B. decreases no change C. decreases decreases D. increases decreases

8


ethanol P CO2(g) + Q

30. Hydrogen, methane and butane are commonly used fuels. Which of the following statements is correct ?

A. Hydrogen is a more environmental friendly fuel than butane. B. Methane burns with a more sooty flame than butane. C. Hydrogen, methane and butane all belong to the same homologous series. D. On complete combustion, one mole of methane releases more carbon dioxide than one

mole of butane.

31. The following is a series of reactions starting from ethanol :

reagent A Na2CO3(aq)

Which of the following correctly describes the reagent A and the product Q ?

Reagent A Product Q

A. dehydrating agent ethene B. dehydrating agent ethane

C. oxidising agent sodium ethanoate D. oxidising agent ethanoic acid


An experiment was performed on the study of the rate of reaction between hydrochloric acid and sodium thiosulphate solution. 10 cm3 portions of 2.0 M hydrochloric acid were added to four separate conical flasks, W, X, Y and Z, each containing sodium thiosulphate solution which was prepared respectively as follows:

conical flask sodium thiosulphate solution

volume of water concentration volume

W 1.0 M 80 cm3 10 cm3

X 1.5 M 60 cm3 30 cm3

Y 2.5 M 30 cm3 60 cm3

Z 3.0 M 20 cm3 70 cm3

32. In which of the above conical flasks does the reaction proceed at the fastest rate ?

A. W B. X

C. Y D. Z

33. Which of the following apparatus should be used when carrying out the above experiment in addition to the conical flasks ?

(1) syringe (2) stop watch (3) measuring cylinder

A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only

D. (1), (2) and (3)



34. Which of the following statements is / are correct concerning the members of the homologous series of alkenes ?

(1) Members of higher molecular mass are often used to make soap. (2) The first few members are often used to make polymers. (3) The members can commonly react with hydrogen halides to give halohydrocarbons.



Directions : Each question below (Questions 35 to 36) 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

35. Catalysts are used in many industrial processes. Catalysts would not affect the percentage of the product in the equilibrium mixture.

36. The reaction of ethanoic acid with ethanol is a Water is one of the products in the reaction of neutralization. ethanoic acid and ethanol.

END OF PART II

END OF SECTION A

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11

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I II

1 H

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3 L

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4 Be

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5 B

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6 C

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7 N

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8 O

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9 F

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12 Mg

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15P

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16 S

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18A

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19K

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20 Ca

40.1

21Sc

45.0

22Ti

47.9

23V

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24 Cr

52.0

25 Mn

54.9

26Fe

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27 Co

58.9

28N

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29 Cu

63.5

30 Zn

65.4

31 Ga

69.7

32 Ge

72.6

33A

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34Se

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35Br

79.9

36 Kr

83.8

37 R

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38Sr

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39Y

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40Zr

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41 Nb

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42 Mo

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43Tc

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44 Ru

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45 Rh

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46Pd

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47 Ag

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48 Cd

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49In

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50Sn

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51Sb

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52 Te

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53 I

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55 Cs

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56 Ba

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80 Hg

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82 Pb

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83B

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84 Po

(209

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85A

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86 Rn

(222

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Fr(2

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88 Ra

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89 *

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104 Rf

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105 Db

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60 Nd

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61 Pm

(145

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62 Sm

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63Eu

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64 Gd

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65 Tb

158.

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66 Dy

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67 Ho

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68E

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69 Tm

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70 Yb

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71 Lu

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Th23

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(231

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92U

238.

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93 Np

(237

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94 Pu

(244

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95 Am

(243

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96 Cm

(247

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97 Bk

(247

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98C

f(2

51)

99E

s(2

52)

100 Fm (257

)

101 Md

(258

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102 No

(259

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103 Lr

(260

)



B Please stick the barcode label here.



CHEMISTRY PAPER 1 ( S a m p l e P a p e r ) SECTION B : Question-Answer Book B


INSTRUCTIONS

(1) Write your Candidate Number in the space provided on Page 1.

(2) Stick barcode labels in the spaces provided on Pages 1, 3, 5 and 7.

(3) Refer to the general instructions on the cover of the Question Book for Section A.

(4) This section consists of TWO parts, Part I and Part II. Part I carries 56 marks and Part II carries 28 marks. The marks to each question are indicated in brackets at the end of the question.

(5) Answer ALL questions in each part. Write your answers in the spaces provided in this Question-Answer Book. Do not write in the margins. Answers written in the margins will not be marked.

(6) Supplementary answer sheets will be provided on request. Write your candidate number, fill in the question number and stick a barcode label on each sheet. Tie them loosely but securely with a string INSIDE this Question-Answer Book.

(7) A Periodic Table is printed on the back of this Question-Answer Book. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table.

Candidate Number

Markers Use Only

Examiners Use Only

Marker No. Examiner No.

Question No. Marks Marks

1

2

3

4

5

6

7

8

9

10

11

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Total


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PART I

Answer ALL questions. Write your answers in the spaces provided.

1 . State whether each of the following statements is true or false. Explain your answer in each case.

(a) The melting point of sodium chloride is much higher than that of methane because the ionic bonding in sodium chloride is much stronger than the covalent bonding in methane.

(b) When concentrated sulphuric acid is diluted, water should be added slowly to the acid.

(c) A is a stronger acid than B, so that pH of an aqueous solution of A must be lower than that of B.

(6 marks)

Answers written in the margins will not be marked.

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2. Polyethene is used in making shopping bags and its monomer is ethene.

(a) Draw the electronic diagram of ethene, showing electrons in the outermost shells only.

(b) Name the type of polymerisation involved in the production of polyethene.

(c) State ONE property of polyethene that makes it suitable for making shopping bags.

(d) (i) Suggest ONE way to dispose of polyethene wastes.

(ii) Give ONE advantage and ONE disadvantage of the way you have suggested in (i). A

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(6 marks) Answers written in the margins will not be marked.

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3. X, Y and Z are three different metals. The table below lists the results of three experiments carried out using the metals or their oxides.

Experiment X Y Z Adding metal to cold water

formation of a colourless gas no observable change no observable change

Adding metal to copper(II) sulphate solution

formation of a colourless gas and a reddish brown solid

formation of a reddish brown solid no observable change

Heating metal oxide with carbon powder no observable change

formation of a solid with metallic lustre

formation of a solid with metallic lustre

(a) What is the colourless gas formed when X is added to cold water ? Suggest a test for the gas.

(b) Name the type of reaction that occurs when the oxide of Y is heated with carbon powder.

(c) Arrange the three metals in order of increasing reactivity. Explain your answer.

(d) Why is a colourless gas formed when X is added to copper(II) sulphate solution ?


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4. A student used the set-up shown below to conduct a microscale experiment on electrolysis.

(a) (i) The initial colour of the drop shown above was green. State the colour change of the liquid around carbon rod A after a current was passed through the circuit for some time. Explain your answer with the help of a half equation.

(ii) A gas was liberated at carbon rod B. What was the gas ? Explain its formation.

(b) Some objects readily available in daily life contain carbon rods which can be used in this experiment. Suggest ONE such object.

(6 marks)

a drop of aqueous sodium sulphate solution with some universal indicator

carbon rod A carbon rod B

microscope slide

d.c. supply +




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5. In an experiment to determine the enthalpy change of combustion of ethanol, a calorimeter containing 200.0 g of water was used. Burning 0.185 g of ethanol caused the temperature of the water in the calorimeter to rise by 6.0C.

(a) Draw a labelled diagram of the set-up used in the experiment.

(b) Assuming that the heat capacity of the calorimeter is negligible, calculate the enthalpy change of combustion of ethanol, in kJ mol1, under the conditions of the experiment.

(Specific heat capacity of water = 4.2 J g1 K1)

(c) State ONE other assumption made in your calculation.

(6 marks)


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6. A negatively charged rod was brought near a jet of water running out from a burette. The jet of water was deflected as shown :

water

(a) With reference to the structure of water, explain why the jet of water was deflected.

(b) State the effect on the jet of water if the negatively charged rod is replaced by a positively charged rod. Explain your answer.

(c) If hexane is used instead of water and a negatively charged rod is brought near the liquid jet, would the liquid jet be deflected ? Explain your answer.

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(6 marks)




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7. Complete the table below by

(a) drawing a three-dimensional diagram for the structure of each solid substance, and

(b) giving an explanation of whether the solid substance is an electrical conductor.

Solid substance Three-dimensional diagram for the structure of the solid substance

Explanation of whether the solid substance is an electrical conductor

diamond

graphite

caesium chloride

(6 marks)


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8. For each of the following experiments, state an expected observation and write a chemical equation for the reaction involved.

(a) adding dilute hydrochloric acid to zinc granules

(b) adding sodium hydroxide solution to iron(II) sulphate solution

(4 marks)




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9. There are four unlabelled reagent bottles each containing one of the white solids listed below :

ammonium chloride, ammonium nitrate, sodium hypochlorite and sodium sulphate

Suggest how you would carry out tests to distinguish the four solids from one another. (9 marks)


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END OF PART I




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PART II co

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Answer ALL questions. Write your answers in the spaces provided.

10. P(g) reacts with Q(g) irreversibly to give R(g). A mixture of P(g) and Q(g) is allowed to react in a closed container of volume 1 dm3 kept at a constant temperature. The graph below shows the changes in concentrations of P(g), Q(g) and R(g) in the container with time.

0.60

0.50

0.40 P(g)

0.30

0.20

Q(g)0.10

R(g)

0.00 0 10 20 30 40

time / minutes

(a) With reference to the above graph, deduce the chemical equation for the reaction in terms of P(g), Q(g) and R(g).

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(b) If the mixture of P(g) and Q(g) is allowed to react at the same temperature but in a closed container of volume 2 dm3 instead, will the time required for the reaction to complete remain the same ? Explain.

(c) Explain why the collisions between molecules of P(g) and Q(g) will not necessarily lead to a reaction.


12


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11. The table below lists the equilibrium constants, Kc, for the reversible reaction

H2(g) + CO2(g) CO(g) + H2O(g)

at three different temperatures.

Temperature/K 500 700 900

Kc 7.76 103 1.23 101 6.03 101

(a) Based on the above information, deduce whether the forward reaction is exothermic or endothermic.

(b) 2.0 mol of H2(g) and 2.0 mol of CO2(g) are allowed to react in a 4.0 dm3 closed container. Calculate the concentration of CO(g), in mol dm3, in the equilibrium mixture at 700 K.

(c) State the effect of an increase in temperature on the rate of the backward reaction.

(5 marks)




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12. Ethyl ethanoate is an ester. It can be prepared by heating a mixture of ethanoic acid and ethanol under reflux in the presence of a catalyst.

(a) What is the catalyst used in the preparation ?

(b) Draw a labelled diagram of the set-up used for heating the mixture under reflux.

(c) Ethyl ethanoate is commonly used as a solvent. Explain why ethyl ethanoate can dissolve iodine but cannot dissolve sodium iodide.

(d) Draw the structure of another ester which has the same molecular formula as ethyl ethanoate, and give its systematic name.

(8 marks)


14

(b)


13. Outline a synthetic route, in not more than three steps, to accomplish each of the following conversions. For each step, give the reagent(s), the conditions and the structure of the organic product.

O (a) CH3CH2CH2Cl CH3CH2C OH

O

CH3CCH3(b) CH3CH=CH2

(6 marks)

14. Compare the acid base properties of sodium oxide (Na2O) and sulphur dioxide (SO2) with reference to how they interact with water molecules.

(4 marks)

END OF PART II

END OF SECTION B

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15

0

PER

IOD

IC T

ABL

E

GR

OU

P

ato

mic

num

ber

I II

1 H

1.0

III

IV

V

VI

VII

2 He

4.0

3 Li

6.9

4 Be

9.0

5 B

10.8

6 C

12.0

7 N

14.0

8 O

16.0

9 F

19.0

10N

e20

.2

11 Na

23.0

12 Mg

24.3

rela

tive

atom

ic m

ass

13A

l27

.0

14Si

28.1

15P

31.0

16S

32.1

17C

l35

.5

18A

r40

.0

19K

39.1

20 Ca

40.1

21Sc

45.0

22Ti

47.9

23V

50.9

24C

r52

.0

25 Mn

54.9

26Fe

55.8

27 Co

58.9

28N

i58

.7

29 Cu

63.5

30 Zn

65.4

31 Ga

69.7

32 Ge

72.6

33A

s74

.9

34Se

79.0

35Br

79.9

36 Kr

83.8

37 R

b85

.5

38Sr

87.6

39Y

88.9

40Zr

91.2

41 Nb

92.9

42 Mo

95.9

43Tc

(98)

44 Ru

101.

1

45 Rh

102.

9

46Pd

106.

4

47 Ag

107.

9

48 Cd

112.

4

49In

114.

8

50Sn

118.

7

51Sb

121.

8

52Te

127.

6

53 I

126.

9

54X

e13

1.3

55C

s13

2.9

56Ba

137.

3

57

*La

138.

9

72H

f17

8.5

73Ta

180.

9

74W

183.

9

75R

e18

6.2

76O

s19

0.2

77Ir

192.

2

78Pt

195.

1

79 Au

197.

0

80 Hg

200.

6

81Tl

204.

4

82Pb

207.

2

83Bi

209.

0

84Po

(209

)

85A

t(2

10)

86 Rn

(222

) 87

Fr(2

23)

88 Ra

(226

)

89 *

*A

c(2

27)

104 Rf

(261

)

105 Db

(262

)

16

* **

58C

e14

0.1

59Pr

140.

9

60 Nd

144.

2

61 Pm

(145

)

62 Sm

150.

4

63 Eu

152.

0

64 Gd

157.

3

65 Tb

158.

9

66 Dy

162.

5

67 Ho

164.

9

68Er

167.

3

69 Tm

168.

9

70 Yb

173.

0

71 Lu

175.

090 T

h23

2.0

91Pa

(231

)

92U

238.

0

93 Np

(237

)

94Pu

(244

)

95 Am

(243

)

96 Cm

(247

)

97 Bk

(247

)

98C

f(2

51)

99Es

(252

)

100 Fm (257

)

101 Md

(258

)

102 No

(259

)

103 Lr

(260

)





CHEMISTRY PAPER 2

( S a m p l e P a p e r )

Time allowed: 1 hour


INSTRUCTIONS

(1) Answer TWO questions in this paper.

(2) Each question carries 20 marks.

(3) Answers are to be written in the Answer Book provided.

(4) A Periodic Table is printed on the back of this Question Book. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table.


Not to be taken away before the end of the examination session

1


Answer any TWO questions.

(1) Industrial Chemistry

(a) In acid solution, chlorate ions (ClO3) slowly oxidize chloride ions to chlorine. The following kinetic data are obtained at 25C :

[ClO3(aq)] [Cl(aq)] [H+(aq)] Initial rate /mol dm3 /mol dm3 /mol dm3 /mol dm3 s1

0.08 0.15 0.20 1.0 105 0.08 0.15 0.40 4.0 105 0.16 0.15 0.40 8.0 105 0.08 0.30 0.20 2.0 105

(i) Write the balanced equation for this reaction.

(ii) Determine the order of the reaction with respect to each reactant.

(iii) Determine the rate constant at this temperature.

(iv) If the rate of the reaction is found to be doubled when the temperature is raised by 10C, deduce the activation energy of the reaction. (Gas constant R = 8.31 JK-1mol-1)

(10 marks)

2


(b) For the industrial preparation of nitric acid from nitrogen, give the chemical reactions and the conditions under which they take place.

(6 marks)

(c) The reaction for the production of methylpropene from 2-bromo-2-methylpropane is represented by the following equation :

CH3 CH3

H3C C CH3 + C2H5ONa H3C C CH2 + C2H5OH + NaBr

Br

(i) With reference to green chemistry, calculate the atom economy of the reaction.

(ii) Apart from atom economy, suggest TWO other factors that scientists should consider in order to conduct a green production process.

(4 marks)



(2) Materials Chemistry

(a) The structure of compound A , which exhibits liquid-crystalline behaviour, is shown below :

O

O

(i) Compound A can be formed by condensation of benzoic acid with cholesterol. Draw the structure of cholesterol.

(ii) What is the difference between true liquid and liquid crystal ?

(iii) Describe briefly the arrangement of the molecules in cholesteric phase liquid crystals.

(iv) Outline the working principle of cholesteric phase liquid crystals in Liquid Crystal Display (LCD).

(10 marks)

4


(b) Plastics can be classified into thermoplastics and thermosetting plastics according to their thermal properties.

(i) Explain, in terms of bonding and structure, why thermoplastics and thermosetting plastics behave differently upon heating.

(ii) Polyethene (PE) is a thermoplastic commonly used in making shopping bags.

(I) Write the chemical equation for the formation of PE from its monomer.

(II) State the repeating unit of PE.

(iii) Some scientists suggested using polylactic acid (PLA) instead of PE to make shopping bags as this can help reduce environmental problems. Part of the structure of PLA is shown below:

CH3 CH3 CH3 CH3

O C C O C C O C C O C C

O H O H O H O H

(I) Draw the structure of the monomer used to make PLA.

(II) Give the systematic name of the monomer.

(III) Name the type of polymerisation for making PLA.

(IV) Explain, in chemical terms, why the disposal of PLA poses less harm to the environment than that of PE.

(10 marks)



(3) Analytical Chemistry

(a) Compound G , with relative molecular mass of 58, has the following composition by mass :

C : 62.1% H : 10.3% O : 27.6%

The infrared and mass spectra of compound G are given below.

Tran

smitt

ance

(%)

Rel

ativ

e In

tens

ity

100

50

0 4000 3000 2000 1500 1000 500

Wavenumber / cm1

10 20 504030 7060 m/z

100

80

60

40

20

0

6


Characteristic Infra-red Absorption Wavenumber Ranges (Stretching modes)

Bond Compound type Wavenumber range /cm1

C=C

C=O

CC CN OH

CH

OH

NH

Alkenes

Aldehydes, ketones, carboxylic acids and derivatives

Alkynes

Nitriles

Acids (hydrogen-bonded)

Alkanes, alkenes, arenes

Alcohols, phenols (hydrogen-bonded)

Amines

1610 to 1680

1680 to 1800

2070 to 2250

2200 to 2280

2500 to 3300

2840 to 3095

3230 to 3670

3350 to 3500

(i) Deduce the molecular formula of compound G .

(ii) From the given spectral information and the molecular formula obtained in (i), deduce the structural formula of compound G.

(iii) Suggest an experiment, with detailed procedures, to support the structure of compound G you have deduced in (ii).

(10 marks)

(b) In an experiment to determine the concentration of ethanol in a brand of spirit, 10.0 cm3 of a sample of the spirit was diluted to 250.0 cm3. 25.0 cm3 portions of the diluted spirit were withdrawn. To each portion, 25.0 cm3 of 0.156 M K2Cr2O7(aq) and excess dilute H2SO4 were added. The mixtures obtained were allowed to stand at room temperature overnight. The excess K2Cr2O7 in each mixture was then titrated against 0.118 M (NH4)2Fe(SO4)2(aq) with an appropriate indicator. The mean titre was 12.23 cm3.

(i) Write an equation for the reaction of ethanol with dichromate ions under acidic condition.

(ii) Give TWO properties of (NH4)2Fe(SO4)2 rendering it to be used as a primary standard in volumetric analysis.

(iii) Suggest a method to test whether the oxidation of ethanol has been completed.

(iv) Calculate the concentration of ethanol, in mol dm-3, in this brand of spirit. (10 marks)

END OF PAPER

7

0

PER

IOD

IC T

ABL

E

GR

OU

P

atom

ic n

umbe

r

I II

1 H

1.0

III

IV

V

VI

VII

2 He

4.0

3 L

i6.

9

4 Be

9.0

5 B

10.8

6 C

12.0

7 N

14.0

8 O

16.0

9 F

19.0

10N

e20

.2

11 Na

23.0

12 Mg

24.3

rela

tive

atom

ic m

ass

13A

l27

.0

14Si

28.1

15P

31.0

16 S

32.1

17C

l35

.5

18A

r40

.0

19K

39.1

20 Ca

40.1

21Sc

45.0

22Ti

47.9

23V

50.9

24 Cr

52.0

25 Mn

54.9

26Fe

55.8

27 Co

58.9

28N

i58

.7

29 Cu

63.5

30 Zn

65.4

31 Ga

69.7

32 Ge

72.6

33A

s74

.9

34Se

79.0

35Br

79.9

36 Kr

83.8

37 R

b85

.5

38Sr

87.6

39Y

88.9

40Zr

91.2

41 Nb

92.9

42 Mo

95.9

43Tc

(98)

44 Ru

101.

1

45 Rh

102.

9

46Pd

106.

4

47 Ag

107.

9

48 Cd

112.

4

49In

114.

8

50Sn

118.

7

51Sb

121.

8

52 Te

127.

6

53 I

126.

9

54X

e13

1.3

55 Cs

132.

9

56 Ba

137.

3

57

*La

138.

9

72H

f17

8.5

73Ta

180.

9

74W

183.

9

75 Re

186.

2

76O

s19

0.2

77Ir

192.

2

78Pt

195.

1

79 Au

197.

0

80 Hg

200.

6

81T

l20

4.4

82 Pb

207.

2

83B

i20

9.0

84 Po

(209

)

85A

t(2

10)

86 Rn

(222

) 87

Fr(2

23)

88 Ra

(226

)

89 *

*A

c(2

27)

104 Rf

(261

)

105 Db

(262

)

8

*

**

58C

e14

0.1

59Pr

140.

9

60 Nd

144.

2

61 Pm

(145

)

62 Sm

150.

4

63Eu

152.

0

64 Gd

157.

3

65 Tb

158.

9

66 Dy

162.

5

67 Ho

164.

9

68E

r16

7.3

69 Tm

168.

9

70 Yb

173.

0

71 Lu

175.

0 90

Th23

2.0

91Pa

(231

)

92U

238.

0

93 Np

(237

)

94 Pu

(244

)

95 Am

(243

)

96 Cm

(247

)

97 Bk

(247

)

98C

f(2

51)

99E

s(2

52)

100 Fm (257

)

101 Md

(258

)

102 No

(259

)

103 Lr

(260

)


HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITY HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION CHEMISTRY PAPER 1 CHEMISTRY PAPER 1 CHEMISTRY PAPER 1

(Sample Paper) (Sample Paper) (Sample Paper) Time allowed: 2 hours 30 minutes

This paper must be answered in English. GENERAL INSTRUCTIONS GENERAL INSTRUCTIONS 1.. There are TWO sections, A and B, in this Paper. Section A carries 36 marks and Section B carries 84 marks. You are advised to finish Section A in about 45 minutes and Section B in about 105 minutes. 1.. There are TWO sections, A and B, in this Paper. Section A carries 36 marks and Section B carries 84 marks. You are advised to finish Section A in about 45 minutes and Section B in about 105 minutes. 1.. There are TWO sections, A and B, in this Paper. Section A carries 36 marks and Section B carries 84 marks. You are advised to finish Section A in about 45 minutes and Section B in about 105 minutes.

2.. Section A consists of multiple-choice questions in this question book, while Section B contains conventional questions printed separately in Question-Answer Book B. 2.. Section A consists of multiple-choice questions in this question book, while Section B contains conventional questions printed separately in Question-Answer Book B.

3.. Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to Section B should be written in the spaces provided in Question-Answer Book B. The Answer Sheet for Section A and the Question-Answer Book for Section B must be handed in separately at the end of the examination. 3.. Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to Section B should be written in the spaces provided in Question-Answer Book B. The Answer Sheet for Section A and the Question-Answer Book for Section B must be handed in separately at the end of the examination.

SECTION A (MULTIPLE-CHOICE QUESTIONS) SECTION A (MULTIPLE-CHOICE QUESTIONS) INSTRUCTIONS FOR SECTION A 1.. Read the instructions on the Answer Sheet carefully. Stick a barcode label and insert the information required in the spaces provided. 1.. Read the instructions on the Answer Sheet carefully. Stick a barcode label and insert the information required in the spaces provided. 1.. Read the instructions on the Answer Sheet carefully. Stick a barcode label and insert the information required 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 SECTION A after the last question. 2.. When told to open this book, you should check that all the questions are there. Look for the words END OF SECTION A after the last question.

3.. All questions carry equal marks. 3.. All questions carry equal marks.

4.. ANSWER ALL QUESTIONS. You should use an HB pencil to mark all your answers on the Answer Sheet. Wrong marks must be completely erased. 4.. ANSWER ALL QUESTIONS. You should use an HB pencil to mark all your answers on the Answer Sheet. Wrong marks must be completely erased.

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. 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. 6.. No marks will be deducted for wrong answers.

Hong Kong Examinations and Assessment Authority All Rights Reserved 2008 Not to be taken away before the end of the examination session This section consists of two parts. There are 24 questions in PART I and 12 questions in PART II. Choose the best answer for each question. .Candidates may refer to the Periodic Table printed on the back of this Question Book.. PART I. Choose the best answer for each question. .Candidates may refer to the Periodic Table printed on the back of this Question Book.. PART I. 1.. Upon cracking, one molecule of decane (C10H22) gives two molecules of propene and one molecule of an alkane ( X ). What is X ? A.. C4H6 A.. C4H6 B.. C4H10 C.. C7H14 D.. 7H16 C

2. .In which of the following compounds does sulphur exhibit the lowest oxidation number ? A.. Na2S2O3 A.. Na2S2O3 B.. MgSO4 C.. 3KHSO

D.. 2S2O7 H

3.. Which of the following correctly describes the sequence of procedures to separate sand, salt and water from a mixture of sand and salt solution ? A. .filtration, evaporation A. .filtration, evaporation B. .filtration, distillation C. .crystallisation, filtration D. .crystallisation, filtration, distillation

4. .The structure of polymer X is shown below. H CHH CHH CHH CHH CHH CH3 3 3

. . . . . .. . .CCCCCC H CHH CHH CH3 3 3

What is the monomer of X ? A.. 1,1-dimethylethene A.. 1,1-dimethylethene B.. 1,2-dimethylethene C. .methylpropene D.. but-1-ene D.. but-1-ene Directions: Questions 5 to 6 refer to the following experiment.

Rust indicator containing potassium hexacyanoferrate(III) solution was poured into the following glass dishes to cover the iron nails, which were wrapped with different metal strips. The dishes were allowed to stand in air for some time. Figuresilver strip zinc strip copper strip magnesium strip dish 1 dish 2 dish 3 dish 4 5. If the iron nail rusts, what would the colour of the rust indicator be around the nail ? A. yellow A. yellow B. brown C. red D. blue

6. In which of the dishes would the iron nail rust ? A. dish 1 only A. dish 1 only B. dish 2 only C. dish 1 and dish 3 only D. dish 2 and dish 4 only

7. The atomic number of an element X is 18. An atom of X has a mass number of 40. The atom has A. 18 protons, 22 neutrons and 18 electrons. A. 18 protons, 22 neutrons and 18 electrons. B. 18 protons, 22 neutrons and 22 electrons. C. 18 protons, 40 neutrons and 18 electrons. D. 22 protons, 22 neutrons and 18 electrons.

8. The following hazard warning labels are displayed on the reagent bottle of an acid. SectFigure

What information about this acid can be obtained from the labels ? A. It is very concentrated and flammable. A. It is very concentrated and flammable. B. It is very concentrated and oxidising. C. It is flammable and corrosive. D. It is corrosive and oxidising.

9.. Which of the following statements concerning alkenes is INCORRECT ? A. .They can decolourise a solution of bromine. A. .They can decolourise a solution of bromine. B. .They can decolourise red litmus solution.

C.. They can decolourise acidified potassium permanganate solution. D.. They can be polymerised to form addition polymers. D.. They can be polymerised to form addition polymers.

10. .Which of the following reactions is endothermic ? A.. Zn(s) + Cu(aq) Zn(aq) + Cu(s)A.. Zn(s) + Cu(aq) Zn(aq) + Cu(s)2+2+

B. .CaCO3(s) + 2H(aq) Ca(aq) + H2O(l) + CO2(g)+2+

C.. 2C4H10(g) + 13O2(g) 8CO2(g) + 10H2O(l) D.. 9H20(l) C2H6(g) + C3H6(g) + C4H8(g) C

11. .Element X has three isotopes, X, X and X. The graph below shows the relative abundances of the isotopes. 206207208

70 70 60 50 40 30 20 10 0 FigureFigureFigure

206 207 208 What is the relative atomic mass of X ? A.. 206.8 A.. 206.8 B.. 207.0 C.. 207.3 D.. 207.5 relative abundance (%)

12. Which of the following combinations concerning the set-up shown below is correct after a current has flowed through the external circuit for some time ? copper(II) sulphate solution V copper rod silver rod .

Mass of anode Colour of copper(II) sulphate solution Mass of anode Colour of copper(II) sulphate solution

A. increases .no change A. increases .no change B. decreases. no change C. increases .becomes lighter D. decreases. becomes lighter

13.. Standard enthalpy changes of several reactions, as denoted by x, y and z respectively, are listed in the table below. Reaction Reaction Reaction Standard enthalpy change / kJ mol1

C(s) + O2(g) CO2(g) C(s) + O2(g) CO2(g) x

H2(g) + 2 1 O2(g) H2O(l) H2(g) + 2 1 O2(g) H2O(l) y

C(s) + 2H2(g) CH4(g) C(s) + 2H2(g) CH4(g) z

For the reaction CH4(g) + 2O2(g) CO2(g) + 2H2O(l), which of the following is a reasonable estimate of its standard enthalpy change ? A. x + y z A. x + y z B.. x y+ z C. x + 2y z D. .x 2y z

14.. 500 cm of calcium hydroxide solution contains 3.7 g of calcium hydroxide. What is the molarity of the solution ? 3

(Relative atomic masses : H = 1.0, O = 16.0, Ca = 40.1) A.. 0.05 MA.. 0.05 M B.. 0.10 M C.. 0.13 M D.. 0.26 M

15.. Which of the following samples of gases contains the smallest number of molecules ? (Relative atomic masses : H = 1.0, C = 12.0, N = 14.0, O = 16.0, S = 32.1) A.. 10 g ofNO2 A.. 10 g ofNO2 B. .2 10 g of CO

C. .2S 10g ofH

D.. 2H4 D.. 2H4 10 g of C


In an experiment to determine the concentration of sulphuric acid in a brand of toilet cleaner, 25.0 cm of the cleaner was first diluted to 250.0 cm with distilled water. Upon titration with 0.950 M sodium hydroxide solution using phenolphthalein as indicator, 25.0 cm of the diluted cleaner required 27.1 cm of the sodium hydroxide solution to reach the end point. 3333

16.. Which of the following types of apparatus should be used to measure 25.0 cm of the toilet cleaner ?3

A.. pipette A.. pipette B. .burette C.. measuring cylinder D.. volumetric flask

17. .What is the colour change at the end point of the titration ? A. .from colourless to pink A. .from colourless to pink B.. from pink to colourless C.. from yellow to red D. .from red to yellow

18. .What is the concentration of sulphuric acid in the undiluted toilet cleaner ? A.. 1.29 M A.. 1.29 M B.. 2.58 M C.. 5.15 M D.. 10.3 M

19.. In an experiment, 10.0 g of KCl(s) was added to 100 cm of water. The mixture was then stirred until all the KCl(s) dissolved. The temperature of the mixture was found to drop by 5.5C. What is the molar enthalpy change, in kJ mol, of the dissolving process of KCl(s) under the conditions of the experiment ?31

(Specific heat capacity of the mixture = 4.2 J g K ; Density of water = 1.0 g cm; .Relative atomic masses: K = 39.1, Cl = 35.5) .113

A. 2.31 A. 2.31 B. 2.54 C.. 17.23 D.. 18.96

20. .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) .(1) .(1) .adding dilute sulphuric acid to the powder

(2). (2). adding sodium hydroxide solution to the powder

(3) .(3) .heating the powder strongly

A.. (1) onlyA.. (1) only B. .(2) only C. .(1) and (3) only D.. (2) and (3) only

21. Consider the following experiment : carbon electrode Y carbon electrode X carbon electrode X carbon electrode X carbon electrode X Figure

dilute hydrochloric acid

dilute hydrochloric acid

gel containing copper(II) dichromate Which of the following statements concerning the experiment are correct ? (1) .(1) .(1) .Gas bubbles are evolved at electrode X.

(2). (2). An orange colour gradually appears in the solution around electrode Y.

(3). (3). The experiment can be used to show that ions migrate towards oppositely charged electrodes.

A.. (1) and (2) only A.. (1) and (2) only B. .(1) and (3) only C. .(2) and (3) only D.. (1), (2) and (3)

22.. Iodine is a solid at room temperature and pressure. Which of the following statements concerning the structure of iodine is/are correct ? (1). (1). (1). Iodine has a giant covalent structure.

(2) .(2) .Iodine molecules are held together by van der Waals forces.

(3). (3). Iodine atoms are held together in pairs by covalent bonds.

A.. (1) only A.. (1) only B. .(2) only C. .(1) and (3) only D.. (2) and (3) only

Directions : Each question below (Questions 23 to 24) 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 23. .23. .23. .Bromine water can be used to distinguish Bromine can be reduced by sodium sulphite to between sodium sulphate solution and sodium colourless bromide ions, but not by sodium sulphite solution. sulphate.

24. .24. .Carbon dioxide and silicon dioxide have similar The atoms of carbon and silicon have the same physical properties. number of electrons in their outermost shells.

END OF PART I END OF PART I END OF PART I PART II

25. .Which of the following changes will NOT increase the initial rate of the reaction between 50 cm of 1 M HCl(aq) and excess calcium carbonate granules ? 25. .Which of the following changes will NOT increase the initial rate of the reaction between 50 cm of 1 M HCl(aq) and excess calcium carbonate granules ? 3

A.. using 100 cmof HCl(aq) instead of 50 cm of HCl(aq) 3 3

B.. using 2 M HCl(aq) instead of 1 M HCl(aq) B.. using 2 M HCl(aq) instead of 1 M HCl(aq)

C.. using 25 cmof 2 M HCl(aq) instead of 50 cm of 1 M HCl(aq) 3 3

D. .using calcium carbonate powder instead of calcium carbonate granules 26. .Which of the following conversions is a substitution reaction ? A.. CH3CH2CH=CH2 CH3CH2CHBrCH3 A.. CH3CH2CH=CH2 CH3CH2CHBrCH3 B. .CH3CH2CH2CH2OH CH3CH2CH2CHO C. .CH3CH2CHOHCH3 CH3CH2CHBrCH3 D.. CH3CH2CH2CO2H CH3CH2CH2CH2OH

27.. 4H8O2 . What is the number of possible structures of the compound ?A compound with an ester functional group has a molecular formula of C

A.. 3 A.. 3 B. .4 C.. 5 D.. 6

28. .Which type of reaction is involved in converting propan-2-ol to propene ? A. .addition A. .addition B.. oxidation C.. dehydration D. .substitution

29. .Consider the following system at equilibrium : A(g) + 2B(g) 2C(g) H = +200 kJ mol 2C(g) H = +200 kJ molFigure-1

What would be the effect on the rates of the forward and backward reactions if the temperature of the system were lowered ? forward reaction rate backward reaction rate forward reaction rate backward reaction rate

A. decreases. increases A. decreases. increases B. decreases. no change C. decreases. decreases D. increases .decreases

ethanol P CO2(g) + Q 30.. Hydrogen, methane and butane are commonly used fuels. Which of the following statements is correct ? A.. Hydrogen is a more environmental friendly fuel than butane. B. .Methane burns with a more sooty flame than butane. B. .Methane burns with a more sooty flame than butane.

C.. Hydrogen, methane and butane all belong to the same homologous series. D.. On complete combustion, one mole of methane releases more carbon dioxide than one mole of butane. 31.. The following is a series of reactions starting from ethanol : 2CO3(aq) 2CO3(aq) reagent A Na

Which of the following correctly describes the reagent A and the product Q ? Reagent A Product QReagent A Product QReagent A Product Q

A.. dehydrating agent ethene B.. dehydrating agent ethane C.. oxidising agent sodium ethanoate D.. oxidising agent ethanoic acid

Directions: Questions 32 to 33 refer to the following information. An experiment was performed on the study of the rate of reaction between hydrochloric acid and sodium thiosulphate solution. 10 cm portions of 2.0 M hydrochloric acid were added to four separate conical flasks, W, X, Y and Z, each containing sodium thiosulphate solution which was prepared respectively as follows: 3

conical flask conical flask conical flask sodium thiosulphate solution volume of water

concentration concentration volume

W W 1.0 M 80 cm3 10 cm3

X X 1.5 M 60 cm3 30 cm3

Y Y 2.5 M 30 cm3 60 cm3

Z Z 3.0 M 20 cm3 70 cm3

32. .In which of the above conical flasks does the reaction proceed at the fastest rate ? A.. W A.. W B. .X C.. Y D.. Z

33. .Which of the following apparatus should be used when carrying out the above experiment in addition to the conical flasks ? (1). (1). (1). syringe

(2). (2). stop watch

(3). (3). measuring cylinder

A.. (1) and (2) only A.. (1) and (2) only B. .(1) and (3) only C. .(2) and (3) only D.. (1), (2) and (3)

34.. Which of the following statements is / are correct concerning the members of the homologous series of alkenes ? (1). (1). (1). Members of higher molecular mass are often used to make soap.

(2) .(2) .The first few members are often used to make polymers.

(3) .(3) .The members can commonly react with hydrogen halides to give halohydrocarbons.

A.. (1) onlyA.. (1) only B. .(2) only C. .(1) and (3) only D.. (2) and (3) only

Directions : Each question below (Questions 35 to 36) 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 35. .35. .35. .Catalysts are used in many industrial processes. Catalysts would not affect the percentage of the product in the equilibrium mixture.

36. .36. .The reaction of ethanoic acid with ethanol is a Water is one of the products in the reaction of neutralization. ethanoic acid and ethanol.

END OF PART II .END OF SECTION A. END OF PART II .END OF SECTION A.

This is a blank page. This is a blank page.

PERIODIC TABLE GROUPatomic numberI II 1 H1.0 III IV V VI VII 2 He4.0 3 Li6.9 4 Be9.0 5 B10.8 6 C12.0 7 N14.0 8 O16.0 9 F19.0 10Ne20.2 11Na23.0 12Mg24.3 relative atomic mass 13Al27.0 14Si28.1 15P31.0 16 S32.1 17Cl35.5 18Ar40.0 19K39.1 20Ca40.1 21Sc45.0 22Ti47.9 23V50.9 24Cr52.0 25Mn54.9 26Fe55.8 27Co58.9 28Ni58.7 29Cu63.5 30Zn65.4 31Ga69.7 32Ge72.6 33As74.9 34Se79.0 35Br79.9 36Kr83.8 37Rb85.5 38Sr87.6 39Y88.9 40Zr91.2 41Nb92.9 42Mo95.9 43Tc(98) 44Ru101.1 45Rh102.9 46Pd106.4 47Ag107.9 48Cd112.4 49In114.8 50Sn118.7 51Sb121.8 52Te127.6 5**** 58Ce140.1 58Ce140.1 58Ce140.1 59Pr140.9 60Nd144.2 61Pm(145) 62Sm150.4 63Eu152.0 64Gd157.3 65Tb158.9 66Dy162.5 67Ho164.9 68Er167.3 69Tm168.9 70Yb173.0 71Lu175.0

90Th232.0 91Pa(231) 90Th232.0 91Pa(231) 92U238.0 93Np(237) 94Pu(244) 95Am(243) 96Cm(247) 97Bk(247) 98Cf(251) 99Es(252) 100 Fm(257) 101Md(258) 102No(259) 103Lr(260)

B. B. B.

Please stick the barcode label here. HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITY HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION CHEMISTRY PAPER 1 (Sample Paper) CHEMISTRY PAPER 1 (Sample Paper) SECTION B : Question-Answer Book B SECTION B : Question-Answer Book B This paper must be answered in English. This paper must be answered in English.

INSTRUCTIONS (1) .Write your Candidate Number in the space provided on Page 1. (1) .Write your Candidate Number in the space provided on Page 1. (1) .Write your Candidate Number in the space provided on Page 1.

(2) .Stick barcode labels in the spaces provided on Pages 1, 3, 5 and 7. (2) .Stick barcode labels in the spaces provided on Pages 1, 3, 5 and 7.

(3) .Refer to the general instructions on the cover of the Question Book for Section A. (3) .Refer to the general instructions on the cover of the Question Book for Section A.

(4) .This section consists of TWO parts, Part I and Part (4) .This section consists of TWO parts, Part I and Part (4) .This section consists of TWO parts, Part I and Part

II. Part I carries 56 marks and Part II carries 28 marks. The marks to each question are indicated in brackets at the end of the question. II. Part I carries 56 marks and Part II carries 28 marks. The marks to each question are indicated in brackets at the end of the question.

(5) .Answer ALL questions in each part. Write your answers in the spaces provided in this Question-Answer Book. Do not write in the margins. Answers written in the margins will not be marked. (5) .Answer ALL questions in each part. Write your answers in the spaces provided in this Question-Answer Book. Do not write in the margins. Answers written in the margins will not be marked.

(6) .Supplementary answer sheets will be provided on request. Write your candidate number, fill in the question number and stick a barcode label on each sheet. Tie them loosely but securely with a string INSIDE this Question-Answer Book. (6) .Supplementary answer sheets will be provided on request. Write your candidate number, fill in the question number and stick a barcode label on each sheet. Tie them loosely but securely with a string INSIDE this Question-Answer Book.

(7) .A Periodic Table is printed on the back of this Question-Answer Book. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table. (7) .A Periodic Table is printed on the back of this Question-Answer Book. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table.

Candidate Number TableTRMarkers Use Only Examiners Use Only

Marker No. Marker No. Examiner No.

Question No. Question No. Marks Marks

1 1

2 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

10 10

11 11

12 12

13 13

14 14

Total Total

Hong Kong Examinations and Assessment Authority All Rights Reserved 2008 Answers written in the margins will not be marked. PART I Answer ALL questions. Write your answers in the spaces provided. 1.. State whether each of the following statements is true or false. Explain your answer in each case. (a) .(a) .(a) .The melting point of sodium chloride is much higher than that of methane because the ionic bonding in sodium chloride is much stronger than the covalent bonding in methane.

(b) .(b) .When concentrated sulphuric acid is diluted, water should be added slowly to the acid.

(c) .(c) .A is a stronger acid than B, so that pH of an aqueous solution of A must be lower than that of B.

(6 marks) Draft as of December 2008 Please stick the barcode label here. 2. Polyethene is used in making shopping bags and its monomer is ethene. (a) (a) (a) Draw the electronic diagram of ethene, showing electrons in the outermost shells only.

(b) (b) Name the type of polymerisation involved in the production of polyethene.

(c) (c) State ONE property of polyethene that makes it suitable for making shopping bags.

(d) (d) (i) Suggest ONE way to dispose of polyethene wastes.

(ii) Give ONE advantage and ONE disadvantage of the way you have suggested in (i). Answers written in the margins will not be marked. (6 marks) Go on to the next page FigureAnswers written in the margins will not be marked. 3. X, Y and Z are three different metals. The table below lists the results of three experiments carried out using the metals or their oxides. Experiment Experiment Experiment X Y Z

Adding metal to cold water Adding metal to cold water formation of a colourless gas no observable change no observable change

Adding metal to copper(II) sulphate solution Adding metal to copper(II) sulphate solution formation of a colourless gas and a reddish brown solid formation of a reddish brown solid no observable change

Heating metal oxide with carbon powder Heating metal oxide with carbon powder no observable change formation of a solid with metallic lustre formation of a solid with metallic lustre

(a) (a) (a) What is the colourless gas formed when X is added to cold water ? Suggest a test for the gas.

(b) (b) Name the type of reaction that occurs when the oxide of Y is heated with carbon powder.

(c) (c) Arrange the three metals in order of increasing reactivity. Explain your answer.

(d) (d) Why is a colourless gas formed when X is added to copper(II) sulphate solution ?

(7 marks) Please stick the barcode label here. Answers written in the margins will not be marked. Answers written in the margins will not be marked. 4. A student used the set-up shown below to conduct a microscale experiment on electrolysis. (a) (i) The initial colour of the drop shown above was green. State the colour change of the liquid around carbon rod A after a current was passed through the circuit for some time. Explain your answer with the help of a half equation. (ii) A gas was liberated at carbon rod B. What was the gas ? Explain its formatiGo on to the next page FigureAnswers written in the margins will not be marked. 5. In an experiment to determine the enthalpy change of combustion of ethanol, a calorimeter containing 200.0 g of water was used. Burning 0.185 g of ethanol caused the temperature of the water in the calorimeter to rise by 6.0C. (a) (a) (a) Draw a labelled diagram of the set-up used in the experiment.

(b) .(b) .(b) .Assuming that the heat capacity of the calorimeter is negligible, calculate the enthalpy change of combustion of ethanol, in kJ mol, under the conditions of the experiment. 1

(Specific heat capacity of water = 4.2 J g K) (Specific heat capacity of water = 4.2 J g K) 11

(c) (c) (c) State ONE other assumption made in your calculation.

(6 marks) Draft as of December 2008 Please stick the barcode label here. 6. A negatively charged rod was brought near a jet of water running out from a burette. The jet of water was deflected as shown : water (a). (a). (a). With reference to the structure of water, explain why the jet of water was deflected.

(b) .(b) .State the effect on the jet of water if the negatively charged rod is replaced by a positively charged rod. Explain your answer.

(c). (c). If hexane is used instead of water and a negatively charged rod is brought near the liquid jet, would the liquid jet be deflected ? Explain your answer.

Answers written in the margins will not be marked. (6 marks) Go on to the next page FigureAnswers written in the margins will not be marked. 7. Complete the table below by (a) (a) (a) drawing a three-dimensional diagram for the structure of each solid substance, and

(b) (b) giving an explanation of whether the solid substance is an electrical conductor.

Solid substance Solid substance Solid substance Three-dimensional diagram for the structure of the solid substance Explanation of whether the solid substance is an electrical conductor

diamond diamond

graphite graphite

caesium chloride caesium chloride

(6 marks) Answers written in the margins will not be marked. 8.. For each of the following experiments, state an expected observation and write a chemical equation for the reaction involved. (a). (a). (a). (a). adding dilute hydrochloric acid to zinc granules

(b). (b). adding sodium hydroxide solution to iron(II) sulphate solution

(4 marks) Go on to the next page FigureAnswers written in the margins will not be marked. Answers written in the margins will not be marked. 9. There are four unlabelled reagent bottles each containing one of the white solids listed below : ammonium chloride, ammonium nitrate, sodium hypochlorite and sodium sulphate Suggest how you would carry out tests to distinguish the four solids from one another. (9 marks) Answers written in the margins will not be marked. Answers written in the margins will not be marked. END OF PART I Go on to the next page FigurePART II PART II concentration / mol dm 3

Answer ALL questions. Write your answers in the spaces provided. 10.. P(g) reacts with Q(g) irreversibly to give R(g). A mixture of P(g) and Q(g) is allowed to react in a closed container of volume 1 dmkept at a constant temperature. The graph below shows the changes in concentrations of P(g), Q(g) and R(g) in the container with time. 3

0.60 0.60 0.50 0.40 P(g) 0.30 0.20 Q(g)0.10 .R(g) .0.00 0 0 10

20 30 30 40

time / minutes

(a). With reference to the above graph, deduce the chemical equation for the reaction in terms of P(g), Q(g) and R(g). Answers written in the margins will not be marked. (b). (b). (b). If the mixture of P(g) and Q(g) is allowed to react at the same temperature but in a closed container of volume 2 dm instead, will the time required for the reaction to complete remain the same ? Explain. 3

(c) .(c) .Explain why the collisions between molecules of P(g) and Q(g) will not necessarily lead to a reaction.

(5 marks) Answers written in the margins will not be marked. 11. .The table below lists the equilibrium constants, Kc, for the reversible reaction 2(g) + CO2(g) H

2O(g) .at three different temperatures. .2O(g) .at three different temperatures. .Figure CO(g) + H

Temperature/K Temperature/K Temperature/K 500 700 900

Kc Kc 7.76 103 1.23 101 6.03 101

(a) .(a) .(a) .Based on the above information, deduce whether the forward reaction is exothermic or endothermic.

(b). (b). 2(g) and 2.0 mol of CO2(g) are allowed to react in a 4.0 dm closed container. Calculate the concentration of CO(g), in mol dm, in the equilibrium mixture at 700 K. 2.0 mol of H33

(c) .(c) .State the effect of an increase in temperature on the rate of the backward reaction.

(5 marks) Go on to the next page FigureAnswers written in the margins will not be marked. 12.. Ethyl ethanoate is an ester. It can be prepared by heating a mixture of ethanoic acid and ethanol under reflux in the presence of a catalyst. (a) .(a) .(a) .(a) .What is the catalyst used in the preparation ?

(b). (b). Draw a labelled diagram of the set-up used for heating the mixture under reflux.

(c). (c). Ethyl ethanoate is commonly used as a solvent. Explain why ethyl ethanoate can dissolve iodine but cannot dissolve sodium iodide.

(d). (d). Draw the structure of another ester which has the same molecular formula as ethyl ethanoate, and give its systematic name.

(8 marks) 13. .Outline a synthetic route, in not more than three steps, to accomplish each of the following conversions. For each step, give the reagent(s), the conditions and the structure of the organic product. O O (a) .CHCHCHCl 322

CHCHC OH Figure32

FigureO FigureCHCCHFigure33

(b) CHCH=CH(b) CHCH=CH32

(6 marks)

14.. Compare the acid base properties of sodium oxide (Na2O) and sulphur dioxide (SO2) with reference to how they interact with water molecules. (4 marks) END OF PART II END OF SECTION B END OF PART II END OF SECTION B

Answers written in the margins will not be marked. PERIODIC TABLE GROUPGROUP atomic number I II 1 H1.0 III IV V VI VII 2 He4.0 3 Li6.9 4 Be9.0 5 B10.8 6 C12.0 7 N14.0 8 O16.0 9 F19.0 10Ne20.2 11Na23.0 12Mg24.3 relative atomic mass 13Al27.0 14Si28.1 15P31.0 16S32.1 17Cl35.5 18Ar40.0 19K39.1 20Ca40.1 21Sc45.0 22Ti47.9 23V50.9 24Cr52.0 25Mn54.9 26Fe55.8 27Co58.9 28Ni58.7 29Cu63.5 30Zn65.4 31Ga69.7 32Ge72.6 33As74.9 34Se79.0 35Br79.9 36Kr83.8 37Rb85.5 38Sr87.6 39Y88.9 40Zr91.2 41Nb92.9 42Mo95.9 43Tc(98) 44Ru101.1 45Rh102.9 46Pd106.4 47Ag107.9 48Cd112.4 49In114.8 50Sn118.7 51Sb121.8 52Te127.6*.**. 58Ce140.1 58Ce140.1 58Ce140.1 59Pr140.9 60Nd144.2 61Pm(145) 62Sm150.4 63Eu152.0 64Gd157.3 65Tb158.9 66Dy162.5 67Ho164.9 68Er167.3 69Tm168.9 70Yb173.0 71Lu175.0

90Th232.0 90Th232.0 91Pa(231) 92U238.0 93Np(237) 94Pu(244) 95Am(243) 96Cm(247) 97Bk(247) 98Cf(251) 99Es(252) 100 Fm(257) 101 Md(258) 102 No(259) 103 Lr(260)

HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITY .HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION .CHEMISTRY PAPER 2 CHEMISTRY PAPER 2

(Sample Paper) (Sample Paper) (Sample Paper)

Time allowed: 1 hour .This paper must be answered in English.. INSTRUCTIONS (1). Answer TWO questions in this paper. (1). Answer TWO questions in this paper. (1). Answer TWO questions in this paper.

(2) .Each question carries 20 marks. (2) .Each question carries 20 marks.

(3) .Answers are to be written in the Answer Book provided. (3) .Answers are to be written in the Answer Book provided.

(4) .A Periodic Table is printed on the back of this Question Book. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table. (4) .A Periodic Table is printed on the back of this Question Book. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table.

Hong Kong Examinations and Assessment Authority All Rights Reserved 2008 Not to be taken away before the end of the examination session Answer any TWO questions. (1). Industrial Chemistry (1). Industrial Chemistry (a). 3) slowly oxidize chloride ions to chlorine. The following kinetic data are obtained at 25C : In acid solution, chlorate ions (ClO

3(aq)] [Cl(aq)] [H(aq)] Initial rate /mol dm /mol dm /mol dm /mol dms [ClO+3333 1

0.08 0.15 0.20 1.0 105

0.08 0.15 0.40 4.0 105

0.16 0.15 0.40 8.0 105

0.08 0.30 0.20 2.0 105

(i) .(i) .(i) .(i) .Write the balanced equation for this reaction.

(ii) .(ii) .Determine the order of the reaction with respect to each reactant.

(iii) .Determine the rate constant at this temperature. (iii) .Determine the rate constant at this temperature.

(iv). If the rate of the reaction is found to be doubled when the temperature is raised by 10C, deduce the activation energy of the reaction. (Gas constant R = 8.31 JKmol) -1-1

(10 marks) (b) .(b) .(b) .(b) .For the industrial preparation of nitric acid from nitrogen, give the chemical reactions and the

conditions under which they take place. (6 marks)

(c). (c). The reaction for the production of methylpropene from 2-bromo-2-methylpropane is represented by the following equation :

CHCHCHCH3. 3

H3C H3C H3C C CH3 + C2H5ONa H3C C CH2 + C2H5OH + NaBr

TRBr

(i) (i) With reference to green chemistry, calculate the atom economy of the reaction.

(ii) (ii) Apart from atom economy, suggest TWO other factors that scientists should consider in order to conduct a green production process. (4 marks)

Figure

(2). Materials Chemistry (2). Materials Chemistry (a). The structure of compound A , which exhibits liquid-crystalline behaviour, is shown below : FigureO.O.

O O O Figure

FigureFigureFigureFigure

(i). (i). (i). Compound A can be formed by condensation of benzoic acid with cholesterol. Draw the structure of cholesterol.

(ii) .(ii) .What is the difference between true liquid and liquid crystal ?

(iii) .Describe briefly the arrangement of the molecules in cholesteric phase liquid crystals. (iv). Outline the working principle of cholesteric phase liquid crystals in Liquid Crystal Display (LCD). (10 marks) SectFigure

(b) .Plastics can be classified into thermoplastics and thermosetting plastics according to their thermal properties. (i). (i). (i). Explain, in terms of bonding and structure, why thermoplastics and thermosetting plastics behave differently upon heating.

(ii). (ii). (ii). Polyethene (PE) is a thermoplastic commonly used in making shopping bags.

(I). (I). (I). Write the chemical equation for the formation of PE from its monomer.

(II). (II). (II). State the repeating unit of PE.

(iii) .Some scientists suggested using polylactic acid (PLA) instead of PE to make shopping bags as this can help reduce environmental problems. Part of the structure of PLA is shown below: CH3 CH3 CH3 CH3 CH3 CH3

O O C C O C C O C C O C C

TRO H O H O H O H

(I) (I) (I) Draw the structure of the monomer used to make PLA.

(II) (II) Give the systematic name of the monomer.

(III) (III) Name the type of polymerisation for making PLA.

(IV) (IV) Explain, in chemical terms, why the disposal of PLA poses less harm to the

TRenvironment than that of PE.

TR(10 marks)

Figure

(3) Analytical Chemistry (3) Analytical Chemistry (a) Compound G , with relative molecular mass of 58, has the following composition by mass : C : 62.1% H : 10.3% O : 27.6% .The infrared and mass spectra of compound G are given below.. C : 62.1% H : 10.3% O : 27.6% .The infrared and mass spectra of compound G are given below.. C : 62.1% H : 10.3% O : 27.6% .The infrared and mass spectra of compound G are given below..

(i) .(i) .(i) .Deduce the molecular formula of compound G .

(ii). (ii). From the given spectral information and the molecular formula obtained in (i), deduce the structural formula of compound G.

Transmittance (%) Relative Intensity 100 50 0 4000 3000 2000 1500 1000 500 Wavenumber / cm1 10 20 504030 7060 m/z 100 80 60 40 20 0 Characteristic Infra-red Absorption Wavenumber Ranges (Stretching modes) Bond Bond Bond Compound type Wavenumber range /cm1

C=C C=O CC CN OH CH OH NH C=C C=O CC CN OH CH OH NH Alkenes Aldehydes, ketones, carboxylic acids and derivatives Alkynes Nitriles Acids (hydrogen-bonded) Alkanes, alkenes, arenes Alcohols, phenols (hydrogen-bonded) Amines 1610 to 1680 1680 to 1800 2070 to 2250 2200 to 2280 2500 to 3300 2840 to 3095 3230 to 3670 3350 to 3500

(iii) .Suggest an experiment, with detailed procedures, to support the structure of compound G you have deduced in (ii). (10 marks) (b). In an experiment to determine the concentration of ethanol in a brand of spirit, 10.0 cm of a sample of the spirit was diluted to 250.0 cm. 25.0 cm portions of the diluted spirit were withdrawn. To each portion, 25.0 cm of 0.156 M K2Cr2O7(aq) and excess dilute H2SO4 were added. The mixtures obtained were allowed to stand at room temperature overnight. The 2Cr2O7 in each mixture was then titrated against 0.118 M (NH4)2Fe(SO4)2(aq) with an appropriate indicator. The mean titre was 12.23 cm. 3333excess K3

(i) .(i) .(i) .Write an equation for the reaction of ethanol with dichromate ions under acidic condition.

(ii) .(ii) .4)2Fe(SO4)2 rendering it to be used as a primary standard in volumetric analysis. Give TWO properties of (NH

(iii) .Suggest a method to test whether the oxidation of ethanol has been completed. (iv). Calculate the concentration of ethanol, in mol dm, in this brand of spirit. (10 marks) -3

END OF PAPER END OF PAPER

GROUPGROUPatomic number I II 1 H1.0 III IV V VI VII 2 He4.0 3 Li6.9 4 Be9.0 5 B10.8 6 C12.0 7 N14.0 8 O16.0 9 F19.0 10Ne20.2 11Na23.0 12Mg24.3 relative atomic mass 13Al27.0 14Si28.1 15P31.0 16 S32.1 17Cl35.5 18Ar40.0 19K39.1 20Ca40.1 21Sc45.0 22Ti47.9 23V50.9 24Cr52.0 25Mn54.9 26Fe55.8 27Co58.9 28Ni58.7 29Cu63.5 30Zn65.4 31Ga69.7 32Ge72.6 33As74.9 34Se79.0 35Br79.9 36Kr83.8 37Rb85.5 38Sr87.6 39Y88.9 40Zr91.2 41Nb92.9 42Mo95.9 43Tc(98) 44Ru101.1 45Rh102.9 46Pd106.4 47Ag107.9 48Cd112.4 49In114.8 50Sn118.7 51Sb121.8 52Te127.6 5

* ** **

58Ce140.1 58Ce140.1 58Ce140.1 59Pr140.9 60Nd144.2 61Pm(145) 62Sm150.4 63Eu152.0 64Gd157.3 65Tb158.9 66Dy162.5 67Ho164.9 68Er167.3 69Tm168.9 70Yb173.0 71Lu175.0

90Th232.0 91Pa(231) 90Th232.0 91Pa(231) 92U238.0 93Np(237) 94Pu(244) 95Am(243) 96Cm(247) 97Bk(247) 98Cf(251) 99Es(252) 100 Fm(257) 101Md(258) 102No(259) 103Lr(260)


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