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General Certificate of Secondary Education 2019 GCSE Chemistry Unit 2 Foundation Tier [GCM21] wEdnESday 12 junE, morninG TIME 1 hour 15 minutes. INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces provided at the top of this page. You must answer the questions in the spaces provided. Do not write outside the boxed area on each page or on blank pages. Complete in black ink only. Do not write with a gel pen. Answer all six questions. INFORMATION FOR CANDIDATES The total mark for this paper is 80. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. Quality of written communication will be assessed in Question 3(d). A Data Leaflet, which includes a Periodic Table of the Elements, is included in this question paper. *20GCM2101* *20GCM2101* Centre Number Candidate Number 11830.03R *GCM21* *GCM21*

*20GCM2101* - CCEA

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Page 1: *20GCM2101* - CCEA

General Certificate of Secondary Education2019

GCSE Chemistry

Unit 2

Foundation Tier

[GCM21]wEdnESday 12 junE, morninG

TIME1 hour 15 minutes.

INSTRUCTIONS TO CANDIDATESWrite your Centre Number and Candidate Number in the spaces provided at the top of this page.You must answer the questions in the spaces provided. Do not write outside the boxed area on each page or on blank pages. Complete in black ink only. Do not write with a gel pen.Answer all six questions.

INFORMATION FOR CANDIDATESThe total mark for this paper is 80.Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question.Quality of written communication will be assessed in Question 3(d).A Data Leaflet, which includes a Periodic Table of the Elements, is included in this question paper.

*20GCM2101*

*20GCM2101*

Centre Number

Candidate Number

11830.03R

*GCM21*

*GCM21*

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1 Iron is extracted from its ore in the Blast Furnace. The extraction involves redox reactions.

(a) (i) Name the ore from which iron is extracted in the Blast Furnace.

[1]

(ii) Apart from iron ore, name one other substance added to the Blast Furnace.

[1]

(b) (i) Name the reducing agent in the Blast Furnace and write balanced symbol equations to show the formation of this compound.

Name

Equations

[6]

(ii) Balance the symbol equation below for the production of iron in the Blast Furnace.

Fe2O3 + CO →  Fe +      CO2 [1]

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(iii) Explain, in terms of oxygen content, why the reaction in (b)(ii) is a redox reaction.

[5]

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2 Ammonia is manufactured in the Haber Process. An iron catalyst is used in this process to increase the rate of the reaction.

The balanced symbol equation for the reversible reaction in the Haber Process is:

N2(g) + 3H2(g) ⇌ 2NH3(g)

(a) (i) Explain how a catalyst increases the rate of a chemical reaction.

[2]

(ii) State two conditions which can be altered to change the direction of a reversible reaction.

1.

2. [2]

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(b) A dynamic equilibrium is achieved in the reaction between nitrogen and hydrogen in the Haber Process.

Complete the following table by placing a tick () in the correct column.

Statement True False

Dynamic equilibrium occurs in a closed system.

Dynamic equilibrium occurs when the rates of the forward and reverse reactions are equal.

Dynamic equilibrium occurs when the rate of the forward reaction is greater than the rate of the reverse reaction.

At equilibrium the amount of reactants is always equal to the amount of products.

At equilibrium the amounts of reactants and products remain constant.

[5]

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(c) In the Haber Process the forward reaction is exothermic.

N2(g) + 3H2(g) ⇌ 2NH3(g)

(i) Explain, in terms of bonds, why this reaction is exothermic.

[3]

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(ii) The covalent bonds which are present in the reactants and products are shown below the equation. Use these bonds and the bond energies given in the table to calculate the energy change for the forward reaction.

N2 + 3H2 ⇌    2NH3

N N + H H ⇌ H

HHN

H H H H                     

HHH

N

Bond Bond Energy/kJ

N N 916

H H 436

N H 386

Energy change = kJ [4]

(iii) Using your answer to (c)(ii) suggest a value for the energy change of the reverse reaction.

[1]

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3 Alkenes are hydrocarbons which may be produced by cracking.

(a) (i) State the meaning of the term hydrocarbon.

[1]

(ii) Write the general formula of the alkenes.

[1]

(b) Write a balanced symbol equation for the complete combustion of C4H8 forming carbon dioxide and water.

[3]

(c) Propene may be produced from the cracking of the hydrocarbon C7H16. One other product is formed in this reaction.

(i) Write a balanced symbol equation for the cracking of C7H16.

[2]

(ii) Name the other product formed in this reaction.

[1]

(iii) Suggest why high temperatures are required for cracking reactions.

[1]

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(d) Identify the functional group present in alkenes and describe a chemical test for this functional group.

Write a balanced symbol equation for the chemical reaction which occurs when ethene is tested in this way.

In this question you will be assessed on your written communication skills including the use of specialist terms.

[6]

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4 Calcium nitrate and calcium chloride are compounds often used in commercial treatments for garden plants.

(a) Calcium nitrate may be formed from the reaction of nitric acid with calcium hydroxide solution. An experiment was carried out during which nitric acid was slowly added from a burette to 25.0 cm3 of calcium hydroxide solution in a conical flask.

(i) An indicator was added to the conical flask to show when the reaction was complete. Name a suitable indicator which could have been used in this experiment.

[1]

(ii) Name a piece of apparatus which was used to accurately measure 25.0 cm3 of calcium hydroxide solution.

[1]

(iii) The balanced symbol equation for the reaction is:

Ca(OH)2 + 2HNO3 → Ca(NO3)2 + 2H2O

Calculate the atom economy when calcium nitrate is made using this reaction.

Show your working out.

Atom economy = % [3]

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(b) Anhydrous calcium chloride is used in an experiment to investigate rusting asshown below. An iron nail is placed in three different test tubes (1, 2, and 3)under different conditions. The test tubes were left for one week.

(i) In which test tube(s) would rusting have occurred after one week?

[1]

(ii) What is the purpose of the oil in test tube 2?

[1]

(iii) What is the purpose of the anhydrous calcium chloride in test tube 3?

[1]

© Chief Examiner / CCEA

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(iv) Describe the appearance of rust.

[2]

(v) What is the chemical name for rust?

[1]

(vi) State one method of preventing the formation of rust.

[1]

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5 Molten lead(II) bromide undergoes electrolysis.

(a) What is meant by the term electrolysis?

[1]

(b) The apparatus below is used to carry out the electrolysis of molten lead(II)bromide.

batterylamp

negative electrodepositive electrode

pipeclay triangle

tripod

heatheatproof mat

crucible containing molten lead(II) bromide

(i) Name the material used to make the electrodes in this electrolysis.

[1]

(ii) State two reasons why this material is used to make the electrodes.

1.

2.

[2]

© Chief Examiner / CCEA

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(iii) Suggest why this electrolysis experiment needs to be carried out in a fumecupboard.

[1]

(iv) What name is given to the positive electrode?

[1]

(c) Complete the table to give details of the electrolysis of molten lead(II) bromide.

Negative electrode Positive electrode

Observations at the electrode silvery grey liquid formed

Name of electrolysis product

[4]

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6 Oxygen and nitrogen are the most abundant gases found in the atmosphere.

(a) (i) State the colour of oxygen gas.

[1]

(ii) State one use for oxygen gas.

[1]

(b) Oxygen gas reacts with both metals and non-metals to form oxides. Complete the following table giving information about the reaction of oxygen gas with the elements magnesium and sulfur.

Magnesium Sulfur

Observations during reaction with oxygen white flame

Appearance of product after reaction

with oxygencolourless gas

Nature of oxide formed (acidic or

basic)

[5]

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(c) (i) State the percentage composition of nitrogen gas in the atmosphere.

[1]

(ii) Explain why nitrogen gas is unreactive.

[2]

(iii) Apart from nitrogen and oxygen, name two other gases which are present in the atmosphere.

1.

2. [2]

THIS IS THE END OF THE QUESTION PAPER

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Permission to reproduce all copyright material has been applied for.In some cases, efforts to contact copyright holders may have been unsuccessful and CCEAwill be happy to rectify any omissions of acknowledgement in future if notified.

For Examiner’suse only

QuestionNumber Marks

123456

TotalMarks

Examiner Number

240632

DO NOT WRITE ON THIS PAGE

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© CCEA 2017

SYMBOLS OF SELECTED IONS

SOLUBILITY IN COLD WATER OF COMMON SALTS, HYDROXIDES AND OXIDES

Negative ions

SolubleAll sodium, potassium and ammonium saltsAll nitratesMost chlorides, bromides and iodidesEXCEPT silver and lead chlorides, bromides and iodidesMost sulfates EXCEPT lead and barium sulfatesCalcium sulfate is slightly soluble

InsolubleMost carbonates EXCEPT sodium, potassium and ammonium carbonatesMost hydroxidesEXCEPT sodium, potassium and ammonium hydroxidesMost oxidesEXCEPT sodium, potassium and calcium oxides which react with water

Name Symbol

Ammonium

Chromium(III) Cr3+

Copper(II) Cu2+

Iron(II) Fe2+

Iron(III) Fe3+

Lead(II) Pb2+

Silver Ag+

Zinc Zn2+

Name SymbolButanoate C3H7COO-

CarbonateDichromateEthanoate CH3COO-

HydrogencarbonateHydroxide OH–

Methanoate HCOO–

Nitrate NOPropanoate C2H5COO–

SulfateSulfi te

NewSpe

cifi ca

tion

Positive ions

© CCEA 2017

For fi rst teaching from September 2017

Data Leafl etIncluding the Periodic Table of the Elements

For the use of candidates takingScience: Chemistry,

Science: Double Awardor Science: Single Award

Copies must be free from notes or additions of anykind. No other type of data booklet or information

sheet is authorised for use in the examinations

gcse examinations

chemistry

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227

89

139

57

256

101

223

87

226

88

261

104

262

105

266

106

264

107

277

108

268

109

271

110

272

111

140

58

141

59

144

60

145

61

150

62

152

63

157

64

159

65

162

66

165

67

167

68

169

69

173

70

175

71232

90

231

91

238

92

237

93

242

94

243

95

247

96

245

97

251

98

254

99

253

100

254

102

257

103

133

55

137

56

178

72

181

73

184

74

186

75

190

76

192

77

195

78

197

79

201

80

89

39

91

40

103

45

85

37

88

38

93

41

96

42

98

43

101

44

106

46

108

47

112

48

131

54222

86

210

85

210

84

209

83

207

82

204

81

84

36

79

34

73

32

40

20

39

19

45

21

48

22

51

23

52

24

55

25

56

26

59

27

59

28

64

29

65

30

11

5

12

6

14

7

16

8

19

9

20

10

4

2

40

18

35.5

17

32

16

31

15

28

14

27

1370

31

75

33

80

35115

49

119

50

122

51

128

52

127

53

23

11

24

12

7

3

9

4

* 58 – 71 Lanthanum series† 90 – 103 Actinium series

a = relative atomic mass

x = atomic symbolb = atomic number

THE PERIODIC TABLE OF ELEMENTSGroup

a

bx

*

1

11 2 3 4 5 6 7

0

285

112Copernicium

(approx)