Cs Chem Hkdse Mock Section b Ee

HKDSE

CS (CHEM)

SECTION B

HKDSE-CS (CHEM) B-1 (Sample Mock Paper) © Times Publishing (Hong Kong) Ltd.1All Rights Reserved

TiMES PubliSHing (Hong Kong) lTD.

Hong Kong DiPloMa of SEConDary EDuCaTion ExaMinaTion

SaMPlE MoCK PaPEr

CoMbinED SCiEnCE — CHEMiSTry

Section b: Question-answer book b

This paper must be answered in English

Name:

Class: （）

Date:

B

INSTRUCTIONS FOR SECTION B

(1) After the announcement of the start of the examination, you should first write your Candidate Information in the space provided on .

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

(3) Answer ALL questions. 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.

(4) An asterisk (*) has been put next to the questions where effective communication is assessed.

(5) Supplementary answer sheets will be provided on request. Write your candidate information, mark the question number box on each sheet, and fasten them with string INSIDE this Question-Answer Book.

(6) No extra time will be given to candidates for filling in the question number boxes after the ‘Time is up’ announcement.

Answers written in the margins will not be marked.

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HKDSE-CS (CHEM) B-2 (Sample Mock Paper) © Times Publishing (Hong Kong) Ltd.2

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

Neon (Ne) contains three isotopes, 1. 20Ne, 21Ne and 22Ne. The relative abundance of 21Ne is 0.27%. The relative atomic mass of Ne is 20.19.

(a) What is an isotope ?

(1 mark)

(b) Find the relative abundance of 20Ne in a natural sample of Ne.

(1 mark)

(c) Explain why Ne is so unreactive.

(1 mark)

(d) Suggest ONE use of Ne in industry.

(1 mark)


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HKDSE-CS (CHEM) B-3 (Sample Mock Paper) © Times Publishing (Hong Kong) Ltd.

Go on to the next page

3

You are given the following reagents:2.

silver, silver nitrate solution, copper, copper(II) nitrate solution,

aluminium, aluminium nitrate solution.

(a) Describe simple experiments to show how the relative reactivity of the three metals, silver, copper and aluminium can be determined. You should use only the reagents given above. You should state the expected observations and explain how you arrive at your answer.

(4 marks)

(b) What are the most appropriate methods for the extraction of the above metals from their oxides ?

(3 marks)


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A solid sample 3. X was known to contain lead(II) nitrate and zinc nitrate.

A student was asked to determine the percentage by mass of lead(II) nitrate in the sample by precipitation method. He was given three aqueous solutions: sodium hydroxide, sodium chloride and sodium sulphate. The student first dissolved 5.00 g of the solid in distilled water. He then added excess sodium sulphate solution to the solution.

(a) Why did the student choose sodium sulphate solution for his experiment ? Rationalize his choice.

(2 marks)

(b) Describe what the student should do to complete his experiment.

(2 marks)

(c) The amount of precipitate collected was 3.25 g. Calculate the percentage by mass of lead(II) nitrate in the sample.

(2 marks)


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5

Sulphuric acid ionizes in water to give sulphate ion and hydroxonium ion (H4. 3O+).

(a) What is a dative covalent bond ? Draw the electron diagram of H3O+, showing electrons in the

outermost shells only. Indicate in the diagram the position of the dative covalent bond.

(2 marks)

(b) Sulphuric acid reacts with magnesium under different conditions to give different products.

(1) State the conditions required and write chemical equations for the reaction between magnesium and sulphuric acid.

(2) State the function of sulphuric acid in each case.

(5 marks)

(c) Concentrated sulphuric acid may also act as a dehydrating agent. Write the chemical equation for its reaction with sugar (C12H22O11) for its dehydration property.

(1 mark)


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Consider the following molecules:5.

CH3CH2CH2OHCH3

CH2 CCOOH

A B C

HOCH2CH2OHNH2

CH3CH2CHCOOHOHCCH2CH2CHO

D E F

(a) Suggest a pair of molecules which may combine to form a condensation polymer. Write the chemical equation for its formation.

(2 marks)

(c) Suggest a molecule which may combine with itself to form the following polymers. Write the chemical equations for their formation.

(i) Condensation polymer

(ii) Addition polymer

(3 marks)

COOHHOOC


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7

Consider the following three reactions, all of them are carried out under room temperature and 6.

pressure:

500 cm(1) 3 of 2.0 M HCl + 500 cm3 of 2.0 M NaOH ∆H1

500 cm(2) 3 of 2.0 M CH3COOH + 500 cm3 of 2.0 M NaOH ∆H2

1 000 cm(3) 3 of 1.0 M HCl + 1 mol of NaOH(s) ∆H3

(a) Write an ionic equation for reaction (1).

(1 mark)

(b) State the name of the enthalpy change represented by ∆H1.

(1 mark)

(c) Arrange the three values ∆H1, ∆H2 and ∆H3 in increasing order of magnitude. Explain your answer.

(3 marks)


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Silver oxide cell (button cell), zinc-carbon cell and lithium ion cell are three types of chemical cells 7.

commonly used in daily life.

The overall chemical reaction of a silver oxide cell is given below:

OH–(aq)Zn(s) + Ag2O(s) ZnO(s) + 2Ag(s)

(a) From the overall chemical reaction given, suggest the half equations for the reactions occurring at the cathode and the anode of the silver oxide cell.

(2 marks)

(b) Silver oxide cell and zinc-carbon cell are called primary cells while lithium ion cell is called secondary cell. What does the statement mean ?

(1 mark)

(c) Decide and explain which of the above three types of cells is suitable for the following electrical devices.

(You need not consider the voltages of the cells.)

(i) TV remote control

(ii) Mobile phone

(4 marks)


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9

An aqueous solution 8. X is believed to contain K+(aq) and an unknown anion Y.

The following experiments are performed on solution X and the results are given below:

Experiment Procedure Observation

1

(a) Add BaCl2(aq) to X, then

(b) Add HCl(aq)

(a) A white precipitate is formed.

(b) White precipitate redissolves and a gas turning acidified potassium dichromate solution green evolves.

2

(a) Add chlorine water to X, then

(b) Add BaCl2(aq), then

(c) Add HCl(aq)

(a) No observable change

(b) A white precipitate is formed.

(c) White precipitate does not redissolve.

(a) Explain how you can identify the presence of K+(aq) in solution X.

(2 marks)

(b) From the results of the two experiments, suggest the identity of anion Y. Explain your answer with appropriate chemical equations.

(3 marks)


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What air pollutants are present in car exhaust ? Write an account on the formation of the air pollutants 9.

and their harmful effects to the environment.

(9 marks)

*


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END OF PAPER


PE

RIO

DIC

TA

BL

E

ato

mic

num

ber

0

I II

1

H

1.

0 II

I IV

V

V

I V

II

2 H

e 4.

0 3

Li

6.9

4 B

e 9.

0

5 B

10

.8

6 C

12

.0

7 N

14

.0

8 O

16

.0

9 F

19

.0

10 Ne

20.2

11

Na

23.0

12 Mg

24.3

re

lati

ve a

tom

ic m

ass

13

Al

27.0

14 Si

28

.1

15 P

31

.0

16 S

32.1

17 Cl

35.5

18 Ar

40.0

19

K

39.1

20 Ca

40.1

21 Sc

45

.0

22 Ti

47.9

23 V

50

.9

24 Cr

52.0

25 Mn

54.9

26 Fe

55.8

27 Co

58.9

28 Ni

58.7

29 Cu

63.5

30 Zn

65.4

31 Ga

69.7

32 Ge

72.6

33 As

74.9

34 Se

79

.0

35 Br

79.9

36 Kr

83.8

37

Rb

85.5

38 Sr

87

.6

39 Y

88

.9

40 Zr

91.2

41 Nb

92.9

42 Mo

95.9

43 Tc

(98)

44 Ru

101.

1

45 Rh

102.

9

46 Pd

106.

4

47 Ag

107.

9

48 Cd

112.

4

49 In

11

4.8

50 Sn

11

8.7

51 Sb

12

1.8

52 Te

127.

6

53 I

126.

9

54 Xe

131.

3 55

Cs

132.

9

56 Ba

137.

3

57

* L

a 13

8.9

72 Hf

178.

5

73 Ta

180.

9

74 W

18

3.9

75 Re

186.

2

76 Os

190.

2

77 Ir

19

2.2

78 Pt

195.

1

79 Au

197.

0

80 Hg

200.

6

81 Tl

204.

4

82 Pb

207.

2

83 Bi

209.

0

84 Po

(209

)

85 At

(210

)

86 Rn

(222

) 87

Fr

(223

)

88 Ra

(226

)

89 *

* A

c (2

27)

104 Rf

(261

)

105 Db

(262

)

*

58

C

e 14

0.1

59 Pr

140.

9

60 Nd

144.

2

61 Pm

(1

45)

62 Sm

15

0.4

63 Eu

152.

0

64 Gd

157.

3

65 Tb

158.

9

66 Dy

162.

5

67 Ho

164.

9

68 Er

167.

3

69 Tm

16

8.9

70 Yb

173.

0

71 Lu

175.

0

**

90 Th

232.

0

91 Pa

(231

)

92 U

23

8.0

93 Np

(237

)

94 Pu

(244

)

95 Am

(2

43)

96 Cm

(2

47)

97 Bk

(247

)

98 Cf

(251

)

99 Es

(252

)

100 Fm

(2

57)

101 Md

(258

)

102 No

(259

)

103 Lr

(260

)

GR

OU

P族

周期表

原子序相對原子質量

Cs Chem Hkdse Mock Section b Ee

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