GCSE Chemistry Practice Paper 4 - Higher Tier (Unofficial)

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Instructions to Students

Use black ink or black ball-point pen.
Fill in the boxes at the top of this page with your details if required.
Answer all questions in the spaces provided.
Do all rough work in this book. Cross through any work you do not want to be marked.
In all calculations, show clearly how you work out your answer.
A Periodic Table is provided as a separate insert if required.
Calculators may be used.

Information for Candidates

This practice paper is designed to support student revision for the GCSE Chemistry examinations. It contains questions covering atomic structure, bonding, quantitative chemistry, chemical changes, and energy changes. The marks for individual questions and parts of questions are shown in round brackets.

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Question 1 [16 Marks]

The periodic table is structured based on atomic number and electronic configurations. Elements in the same group exhibit similar chemical properties.

(2)

(a) Write the electronic configuration of:

A sodium atom (atomic number = 11)
A chlorine atom (atomic number = 17)

(3)

(b) Across Period 3 (from sodium to argon), the atomic radius of the elements decreases. Explain why the atomic radius decreases across a period.

(4)

(c) Sodium is a Group 1 alkali metal, and chlorine is a Group 7 halogen. Compare the physical properties of Group 1 metals with Group 7 non-metals.

(7)

(d) Explain, in terms of electronic configurations and atomic structures, why reactivity increases down Group 1 but decreases down Group 7.

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Question 2 [16 Marks]

Ammonia (NH3) is a gas at room temperature, having a simple molecular structure with covalent bonds.

(3)

(a) Draw a dot-and-cross diagram to show the bonding in a molecule of ammonia (NH3). Show only the outer shell electrons.

(6)

(b) Compare the structures and bonding of ice (solid water) and sodium chloride. In your answer, you should specify the type of structure, the types of particles involved, and the forces holding the structures together for both substances.

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This resource is an independent educational tool created to support student revision. It is completely independent and is not endorsed by, affiliated with, or sponsored by any official examination board. All trademarked terms are used under Nominative Fair Use purely for descriptive compatibility indexing. Licensed for individual personal use only.
Chemistry Made Easy is an independent resource. Not affiliated with or endorsed by AQA, Pearson Edexcel, or the IBO.

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(3)

(c) Ice melts at 0 degrees Celsius, whereas sodium chloride melts at 801 degrees Celsius. Explain this difference in melting points by referring to the structures and bonding of both substances.

(4)

(d) Pure water does not conduct electricity, and solid sodium chloride does not conduct electricity. However, molten sodium chloride conducts electricity. Explain these observations in terms of particles and movement.

Question 3 [6 Marks]

Graphite and graphene are both allotropes of carbon with giant covalent structures.

(6)

(a) Explain, in terms of structure and bonding, why graphite is soft and can conduct electricity, whereas graphene is extremely strong and has high electrical conductivity.

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Chemistry Made Easy is an independent resource. Not affiliated with or endorsed by AQA, Pearson Edexcel, or the IBO.

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Question 4 [25 Marks]

Copper metal can be extracted by heating black copper(II) oxide with carbon powder. The chemical equation for the reaction is:

2CuO(s) + C(s) → 2Cu(s) + CO2(g)

(6)

(a) A student heats 15.9 g of copper(II) oxide (CuO) with 2.40 g of carbon powder (C). Show by calculation which reactant is the limiting reactant, and calculate the maximum theoretical mass of copper metal that can be produced.
Relative atomic masses (Ar): C = 12.0; O = 16.0; Cu = 63.5

(3)

(b) Upon completing the reaction, the student obtains 11.2 g of copper metal. Calculate the percentage yield of copper and suggest two reasons why the yield is less than the theoretical maximum.

(3)

(c) Calculate the percentage atom economy for the production of copper metal in this reaction.
Equation: 2CuO(s) + C(s) → 2Cu(s) + CO2(g)
Relative atomic masses (Ar): C = 12.0; O = 16.0; Cu = 63.5

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This resource is an independent educational tool created to support student revision. It is completely independent and is not endorsed by, affiliated with, or sponsored by any official examination board. All trademarked terms are used under Nominative Fair Use purely for descriptive compatibility indexing. Licensed for individual personal use only.
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(7)

(d) A student performs a titration to standardise a phosphoric acid (H3PO4) solution. The balanced equation for the neutralisation reaction is:

H3PO4(aq) + 3NaOH(aq) → Na3PO4(aq) + 3H2O(l)

The student titrates 25.0 cm3 of the phosphoric acid solution against 30.0 cm3 of a 0.200 mol/dm3 sodium hydroxide (NaOH) solution. Calculate the concentration of the phosphoric acid solution in:

mol/dm3 (Give your answer to 3 significant figures)
g/dm3 (Give your answer to 3 significant figures)

Relative atomic masses (Ar): H = 1.0; O = 16.0; Na = 23.0; P = 31.0

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(e) Sodium thiosulfate (Na2S2O3) reacts with dilute hydrochloric acid to form a cloudy yellow precipitate of sulfur. A student uses the disappearing cross experiment to investigate how concentration affects reaction rate.

(3)

(i) Describe a method the student should use to investigate how the concentration of sodium thiosulfate affects the rate of this reaction. Refer to the diagrams and state how rate is calculated.

(3)

(ii) Write the balanced chemical equation for the reaction between sodium thiosulfate (Na2S2O3) and hydrochloric acid (HCl) to produce sodium chloride, sulfur, sulfur dioxide, and water. Include state symbols.

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This resource is an independent educational tool created to support student revision. It is completely independent and is not endorsed by, affiliated with, or sponsored by any official examination board. All trademarked terms are used under Nominative Fair Use purely for descriptive compatibility indexing. Licensed for individual personal use only.
Chemistry Made Easy is an independent resource. Not affiliated with or endorsed by AQA, Pearson Edexcel, or the IBO.

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Question 5 [23 Marks]

Electrolysis is the decomposition of an electrolyte using an electric current. Molten zinc chloride (ZnCl2) is electrolysed using inert carbon electrodes.

(6)

(a) Describe the experimental setup and the chemical changes that occur during the electrolysis of molten zinc chloride. Explain how the products are formed and where they are discharged.

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(b) Write half-equations for the reactions occurring at each electrode during the electrolysis of molten zinc chloride:

(2)

(i) At the negative electrode (cathode)

(2)

(ii) At the positive electrode (anode)

(3)

(c) Explain why zinc chloride can conduct electricity when molten but cannot conduct electricity when in the solid state.

Dilute hydrochloric acid is a strong acid, and dilute ethanoic acid is a weak acid.

(2)

(d) (i) Explain the difference between a strong acid and a weak acid in terms of their ionisation in aqueous solution.

(5)

(ii) The pH scale is logarithmic. The relationship between pH and hydrogen ion concentration [H+] is given by the formula pH = -log10[H+]. Using this relationship, prove mathematically that when a solution of hydrochloric acid is diluted to increase its pH by exactly 1 unit, the hydrogen ion concentration decreases by a factor of 10. Show also how the hydrogen ion concentration changes when pH increases from 2.00 to 5.00.

(3)

(iii) Explain why a 0.100 mol/dm3 solution of ethanoic acid has a higher pH than a 0.100 mol/dm3 solution of hydrochloric acid.

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Question 6 [14 Marks]

A student investigates the reactivity series of metals by measuring the temperature rise when different metals react with dilute hydrochloric acid.

(6)

(a) (i) Describe a method the student could use to compare the reactivity of magnesium, zinc, iron, and copper by measuring temperature changes. Your description should include the apparatus used and how the results can be used to arrange the metals in order of reactivity.

(2)

(ii) State two variables that must be controlled in this investigation to ensure a fair comparison.

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A student investigates the temperature change when citric acid reacts with sodium hydrogencarbonate (RP4). They record a temperature drop during the reaction.

(6)

(b) Explain why the reaction between citric acid and sodium hydrogencarbonate is described as endothermic. In your answer, refer to the temperature change, the bond breaking/forming energy changes, and describe the features of a reaction profile diagram for this process.

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Group 1

Group 2

Transition Metals

Group 3

Group 4

Group 5

Group 6

Group 7

Group 0

KEY

relative atomic mass

H

atomic symbol

name

atomic (proton) number

* Lanthanides

** Actinides

1 H Hydrogen 1

4 He Helium 2

7 Li Lithium 3

9 Be Beryllium 4

11 B Boron 5

12 C Carbon 6

14 N Nitrogen 7

16 O Oxygen 8

19 F Fluorine 9

20 Ne Neon 10

23 Na Sodium 11

24 Mg Magnesium 12

27 Al Aluminium 13

28 Si Silicon 14

31 P Phosphorus 15

32 S Sulfur 16

35.5 Cl Chlorine 17

40 Ar Argon 18

39 K Potassium 19

40 Ca Calcium 20

45 Sc Scandium 21

48 Ti Titanium 22

51 V Vanadium 23

52 Cr Chromium 24

55 Mn Manganese 25

56 Fe Iron 26

59 Co Cobalt 27

59 Ni Nickel 28

63.5 Cu Copper 29

65 Zn Zinc 30

70 Ga Gallium 31

73 Ge Germanium 32

75 As Arsenic 33

79 Se Selenium 34

80 Br Bromine 35

84 Kr Krypton 36

85.5 Rb Rubidium 37

88 Sr Strontium 38

89 Y Yttrium 39

91 Zr Zirconium 40

93 Nb Niobium 41

96 Mo Molybdenum 42

98 Tc Technetium 43

101 Ru Ruthenium 44

103 Rh Rhodium 45

106 Pd Palladium 46

108 Ag Silver 47

112 Cd Cadmium 48

115 In Indium 49

119 Sn Tin 50

122 Sb Antimony 51

128 Te Tellurium 52

127 I Iodine 53

131 Xe Xenon 54

133 Cs Cesium 55

137 Ba Barium 56

139 La* Lanthanum 57

178.5 Hf Hafnium 72

181 Ta Tantalum 73

184 W Tungsten 74

186 Re Rhenium 75

190 Os Osmium 76

192 Ir Iridium 77

195 Pt Platinum 78

197 Au Gold 79

201 Hg Mercury 80

204 Tl Thallium 81

207 Pb Lead 82

209 Bi Bismuth 83

209 Po Polonium 84

210 At Astatine 85

222 Rn Radon 86

223 Fr Francium 87

226 Ra Radium 88

227 Ac** Actinium 89

267 Rf Rutherfordium 104

268 Db Dubnium 105

269 Sg Seaborgium 106

270 Bh Bohrium 107

269 Hs Hassium 108

278 Mt Meitnerium 109

281 Ds Darmstadtium 110

282 Rg Roentgenium 111

285 Cn Copernicium 112

286 Nh Nihonium 113

289 Fl Flerovium 114

289 Mc Moscovium 115

293 Lv Livermorium 116

294 Ts Tennessine 117

294 Og Oganesson 118

140 Ce Cerium 58

141 Pr Praseodymium 59

144 Nd Neodymium 60

145 Pm Promethium 61

150 Sm Samarium 62

152 Eu Europium 63

157 Gd Gadolinium 64

159 Tb Terbium 65

162.5 Dy Dysprosium 66

165 Ho Holmium 67

167 Er Erbium 68

169 Tm Thulium 69

173 Yb Ytterbium 70

175 Lu Lutetium 71

232 Th Thorium 90

231 Pa Protactinium 91

238 U Uranium 92

237 Np Neptunium 93

244 Pu Plutonium 94

243 Am Americium 95

247 Cm Curium 96

247 Bk Berkelium 97

251 Cf Californium 98

252 Es Einsteinium 99

257 Fm Fermium 100

258 Md Mendelevium 101

259 No Nobelium 102

266 Lr Lawrencium 103

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This resource is an independent educational tool created to support student revision. It is completely independent and is not endorsed by, affiliated with, or sponsored by any official examination board. All trademarked terms are used under Nominative Fair Use purely for descriptive compatibility indexing. Licensed for individual personal use only.
Chemistry Made Easy is an independent resource. Not affiliated with or endorsed by AQA, Pearson Edexcel, or the IBO.