GCSE Chemistry Practice Paper 5

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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 and the periodic table, bonding and properties, 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 the properties and electronic configurations of the elements.

(6)

(a) Compare the physical and chemical properties of transition metals with Group 1 (alkali) metals. In your answer, you must give at least two physical and two chemical differences, and identify one industrial application of transition metals that Group 1 metals do not share.

(b) Iron (atomic number = 26) and zinc (atomic number = 30) are transition metals.

(2)

(i) Write the electronic configuration (number of electrons in each shell) for an iron atom (Fe).

(2)

(ii) Write the electronic configuration (number of electrons in each shell) for a zinc atom (Zn).

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(6)

(c) Explain the trends in boiling point and density down Group 0 (the noble gases). Your explanation should refer to the atomic structure, atomic size, and the nature of the forces between the atoms.

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Question 2 [22 Marks]

Carbon forms a variety of allotropes, including fullerenes and carbon nanotubes, which have unique structures and properties.

(6)

(a) Describe the structure and bonding in a carbon nanotube. Explain how this structure relates to its high tensile strength and high electrical conductivity.

(6)

(b) Describe the structure of Fullerene C60. Explain why Fullerene C60 has a lower melting point than diamond, even though both substances are allotropes of carbon.

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(4)

(c) Compare the potential technological uses of carbon nanotubes and fullerenes, giving one specific application for each and explaining how the properties of the substance make it suitable for that application.

(6)

(d) Pure copper is relatively soft and malleable. Brass is an alloy made of copper and zinc. Explain, in terms of structure and bonding, why brass is harder and less malleable than pure copper.

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Question 3 [25 Marks]

Magnesium reacts with aqueous copper(II) sulfate in a displacement reaction to form magnesium sulfate solution and copper metal. The balanced chemical equation is:

Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s)

(2)

(a) State two visual observations that would confirm that this displacement reaction is taking place.

(6)

(b) A student reacts 3.00 g of magnesium ribbon with 16.0 g of copper(II) sulfate (CuSO4) in solution. Show by calculation which reactant is the limiting reactant, and calculate the maximum theoretical mass of copper metal (Cu) that could be produced. Give your answer to 3 significant figures.
Relative atomic masses (Ar): Mg = 24.3; S = 32.1; O = 16.0; Cu = 63.5

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(6)

(c) A student carries out a titration to determine the concentration of a sodium carbonate (Na2CO3) solution.
The student titrates 25.0 cm3 of the sodium carbonate solution against 22.4 cm3 of 0.150 mol/dm3 hydrochloric acid (HCl) to reach the end point.
The balanced equation for the reaction is:

Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g)

Calculate the concentration of the sodium carbonate solution in mol/dm3 and in g/dm3. Give your answers to 3 significant figures.
Relative atomic masses (Ar): H = 1.0; C = 12.0; O = 16.0; Na = 23.0

(3)

(d) In the displacement reaction described in part (b), the student actually obtained 5.08 g of copper. Calculate the percentage yield of copper. Give your answer to 3 significant figures.

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(2)

(e) The student used a volumetric pipette with an uncertainty of +/- 0.06 cm3 to measure the 25.0 cm3 of sodium carbonate solution. Calculate the percentage uncertainty of this measurement.

(6)

(f) Calculate the percentage atom economy for the reaction to produce sodium chloride (NaCl) as the desired product in the titration reaction. Give your answer to 3 significant figures.
Equation: Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g)
Relative atomic masses (Ar): H = 1.0; C = 12.0; O = 16.0; Na = 23.0; Cl = 35.5

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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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Question 4 [23 Marks]

Electrolysis can be used to decompose ionic compounds when they are molten or in aqueous solution.

(a) A student electrolyses aqueous copper(II) chloride (CuCl2) using inert graphite electrodes.

(2)

(i) Write the balanced ionic half-equation, including state symbols, for the reaction that occurs at the anode (positive electrode).

(2)

(ii) Write the balanced ionic half-equation, including state symbols, for the reaction that occurs at the cathode (negative electrode).

(4)

(iii) Explain why copper metal is deposited at the cathode rather than hydrogen gas, and why chlorine gas is produced at the anode rather than oxygen gas. Refer to the reactivity series of metals and the rules of selective discharge in aqueous solutions.

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(b) Acids release hydrogen ions (H+) when dissolved in water. The concentration of H+ ions determines the pH of a solution.

(2)

(i) Hydrochloric acid (HCl) is a strong acid, whereas ethanoic acid (CH3COOH) is a weak acid. Explain what is meant by 'strong acid' and 'weak acid' in terms of dissociation or ionisation.

(4)

(ii) Show mathematically how a decrease of 1.0 unit on the pH scale corresponds to a tenfold increase in the concentration of hydrogen ions [H+] in the solution. You must include a base-10 logarithm explanation in your answer.

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A student investigates the mass changes at the electrodes during the active electrolysis of copper(II) sulfate solution using copper electrodes.

(5)

(c) (i) Explain the changes in mass observed at each electrode during this electrolysis. Link your explanation to the chemical reactions happening at the surfaces of the copper anode and the copper cathode.

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(4)

(ii) Write the balanced ionic half-equations, including state symbols, for the oxidation and reduction processes occurring at the electrodes in this experiment.

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Question 5 [14 Marks]

A student investigates the rate of reaction between calcium carbonate (marble chips) and dilute hydrochloric acid. The equation for the reaction is:

CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g)

(5)

(a) The student sets up the apparatus as shown in the diagram to measure the volume of carbon dioxide gas produced over time. Explain how and why the rate of reaction changes over time from the start of the reaction until it completely stops. Refer to particles and collision theory in your answer.

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(4)

(b) The student recorded the volume of carbon dioxide gas collected at regular intervals:

At 0 seconds: 0 cm3
At 10 seconds: 22 cm3
At 20 seconds: 38 cm3
At 30 seconds: 48 cm3
At 40 seconds: 54 cm3
At 50 seconds: 57 cm3
At 60 seconds: 57 cm3

Calculate the mean rate of reaction during the first 20 seconds of the reaction. Show your working and state the units.

(3)

(c) In a second investigation, the student compares the energy released per gram by the combustion of different alcohols (methanol, ethanol, propanol) using a copper calorimeter setup. Explain why the temperature rise recorded in this simple calorimeter experiment is always significantly lower than the theoretical temperature rise calculated from standard combustion data. Suggest two modifications to the setup that would improve the accuracy of these results.

(2)

(d) Write the balanced chemical symbol equation for the complete combustion of ethanol (C2H5OH).

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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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