OxfordAQA International GCSE Chemistry: Metals (9202) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover section 3.3.1 Metals of the OxfordAQA International GCSE Chemistry (9202) specification, Version 6.2, for exams May/June 2018 onwards: the opening statements 3.3.1 a to c, the reactivity series (3.3.1.1 a to i) and metal carbonates (3.3.1.2 a and b). The qualification is not tiered. Questions 7, 8 and 11 are longer problems that combine several statements.

Learn the content first with the Metals study guide and the Metals revision notes. Free diagnostics help you decide what to revise next.

Questions

1. A lump of gold is beaten into a very thin sheet.

(a) Explain, in terms of structure, why gold can be beaten into a sheet without breaking. [2] (b) Explain why gold conducts electricity. [2]

2. A foundry is choosing a material for a ship’s propeller, which turns in sea water for many years.

Material	Composition by mass	Relative hardness	Corrosion in sea water	Relative cost
J	88% copper, 12% tin	7	very slow	medium
K	60% copper, 40% zinc	6	slow; zinc is gradually lost	low
L	99.9% copper	3	very slow	medium

(a) Explain why J and K are alloys but L is not. [1] (b) Calculate the mass of tin in a 25.0 kg propeller made from J. [2] (c) Use the data to choose the best material for the propeller. Justify your choice by comparing it with the other two. [3]

3. In a house, copper is used for the coil inside a hot-water cylinder and for the cable that supplies an electric oven. Explain why copper is suitable for both of these uses. [3]

4. Small pieces of four metals, A to D, are tested with cold water and with dilute hydrochloric acid. The metals are calcium, copper, iron and lithium.

Metal	Cold water	Dilute hydrochloric acid
A	sinks; fizzes steadily; water turns cloudy	not tested
B	no visible reaction	slow bubbles
C	floats; fizzes steadily; does not melt	not tested
D	no reaction	no reaction

(a) Identify metals A, B, C and D. [4] (b) Give the balanced symbol equation when metal A reacts with water. [2]

5. A student adds pieces of magnesium, zinc, iron and an unknown metal X to solutions of each metal’s sulfate. A tick means a reaction was seen.

Metal added	Magnesium sulfate	Zinc sulfate	Iron(II) sulfate	X sulfate
Magnesium	–	✓	✓	✓
Zinc	✗	–	✓	✓
Iron	✗	✗	–	✗
X	✗	✗	✓	–

(a) Use the results to rank all four metals from most to least reactive. [2] (b) X forms X²⁺ ions. Write the ionic equation for the reaction of X with iron(II) sulfate solution. [1] (c) Explain, in terms of electrons, which species is oxidised and which is reduced in your equation for (b). [2]

6. Gold is found in the ground as the metal. Calcium is found only in compounds.

(a) Explain why gold is found as the metal. [1] (b) Calcium is more reactive than carbon. Suggest how calcium metal is obtained from calcium chloride, and explain why the calcium produced is expensive. [3]

7. Some iron ores contain magnetite, Fe₃O₄. In a blast furnace, carbon monoxide reduces it:

Fe₃O₄ + 4CO → 3Fe + 4CO₂

(a) Name two raw materials, other than the iron ore, that are added to a blast furnace. [2] (b) Write a balanced equation for the formation of carbon monoxide from carbon dioxide in the furnace. [1] (c) Identify the substance that is reduced in the reaction above. Give a reason for your answer. [2] (d) Calculate the maximum mass of iron that can be obtained from 464 tonnes of Fe₃O₄. (Aᵣ: Fe = 56, O = 16) [3]

8. A mining company has a large heap of waste rock that contains only a small percentage of copper compounds.

(a) Describe how a phytomining process would recover copper compounds from this heap. [2] (b) State what bacteria produce when the heap is treated by bioleaching. [1] (c) The solution from the heap contains copper sulfate. Scrap iron is added to it. Write the ionic equation for the reaction and explain why it is a redox reaction. [3] (d) Calculate the mass of iron that reacts when 16.0 kg of copper is produced. (Aᵣ: Fe = 56, Cu = 64) [3] (e) Instead, some of the copper sulfate solution is electrolysed using carbon electrodes. Write the half equation for the reaction at each electrode. [2]

9. The table shows illustrative energy data for producing a metal.

Source of metal	Energy needed per kg / MJ
Extracted from ore	60.0
Recycled scrap	9.0

(a) Calculate the percentage of energy saved by recycling instead of extracting from ore. [2] (b) Calculate the energy saved when 250 kg of the metal is recycled instead of extracted. [1] (c) Give two reasons, other than saving energy, why metals should be recycled. [2]

10. A student heats 4.20 g of a white metal carbonate to constant mass. A white solid of mass 2.00 g remains. The solid stays white while hot and when cold. The carbonate is magnesium, zinc or calcium carbonate.

(a) Calculate the mass of carbon dioxide given off. [1] (b) Show that the results fit magnesium carbonate and not calcium carbonate. (Aᵣ: Mg = 24, Ca = 40, C = 12, O = 16) [3] (c) Explain how the colour of the residue rules out zinc carbonate. [1] (d) Another student suggests repeating the test with sodium carbonate. Predict what would happen to its mass in a Bunsen flame. [1]

11. 2.50 g of zinc carbonate, ZnCO₃, is added to excess dilute sulfuric acid.

(a) Write the balanced symbol equation for this reaction. Name the salt formed. [2] (b) Describe a test to show that the gas given off is carbon dioxide. Give the result. [2] (c) Calculate the volume of carbon dioxide produced, in cm³. (Aᵣ: Zn = 65, C = 12, O = 16; one mole of gas occupies 24 dm³ at room temperature and pressure) [3]

Answers

1. (a) Gold atoms are arranged in layers [1]. The layers slide over each other when the gold is beaten, so it changes shape rather than breaking [1]. (b) Gold has delocalised electrons [1] that move through the structure and carry charge [1]. Examiner insight: An answer about “ions moving” in a solid metal usually gains no credit for (b); the moving particles must be electrons.

2. (a) J and K are mixtures of two metals; L is (almost) a single element [1]. (b) Mass of tin = 12/100 × 25.0 [1] = 3.00 kg [1]. (c) Choose J [1]. J is harder than L, so it keeps its shape better, and corrodes more slowly than K [1]. K is cheaper but loses zinc in sea water, and L is too soft [1]. Examiner insight: Full credit for “justify by comparing” needs a data-based reason for rejecting each other material.

3. Good conductor of heat, so it heats the water in the cylinder [1]. Good conductor of electricity, so it suits the oven cable [1]. It bends into a coil but is hard enough to keep its shape, and does not react with water [1]. Examiner insight: Link every property to a use; a bare list of properties loses credit.

4. (a) A = calcium [1]; B = iron [1]; C = lithium [1]; D = copper [1]. (b) Ca + 2H₂O → Ca(OH)₂ + H₂: correct formulae [1]; balanced [1]. Examiner insight: For (b), check the hydroxide formula from the ion charges: calcium forms Ca²⁺, so it is Ca(OH)₂, not CaOH.

5. (a) Magnesium, zinc, X, iron: magnesium first and iron last [1]; zinc above X [1]. (b) X + Fe²⁺ → X²⁺ + Fe [1] (c) X atoms lose electrons, so X is oxidised [1]. Fe²⁺ ions are reduced because they gain electrons [1]. Examiner insight: In (c) name the particles precisely: “X atoms” and “iron(II) ions”. Writing “iron is oxidised” or leaving out the ion makes the answer ambiguous.

6. (a) Gold is very unreactive, so it has not combined with other elements [1]. (b) By electrolysis [1] of molten calcium chloride [1]. Electrolysis uses large amounts of energy, which makes the metal expensive [1]. Examiner insight: “Electrolysis of calcium chloride” without “molten” is incomplete; the compound must be melted so the ions can move.

7. (a) Any two from: coke (carbon); limestone; hot air [1] [1]. (b) CO₂ + C → 2CO [1] (c) Fe₃O₄ (magnetite) is reduced [1] because it loses oxygen [1]. (d) Mᵣ Fe₃O₄ = 232 [1]. Amount = 464 ÷ 232 = 2.00 million mol, so iron = 6.00 million mol [1]. Mass = 6.00 × 56 = 336 tonnes [1]. Examiner insight: In (d) a mass-ratio method (232 t of ore gives 168 t of iron) is equally creditworthy if the working is shown.

8. (a) Plants grown on the heap absorb copper compounds [1]. They are harvested and burned; the ash contains copper compounds [1]. (b) A leachate (solution) containing copper compounds [1]. (c) Fe + Cu²⁺ → Fe²⁺ + Cu [1]. Iron atoms lose electrons and are oxidised [1]; copper ions gain electrons and are reduced, so both happen together [1]. (d) Amount of copper = 16.0 ÷ 64 = 0.250 kmol [1]. Ratio Fe : Cu = 1 : 1, so 0.250 kmol of iron [1]. Mass = 0.250 × 56 = 14.0 kg [1]. (e) Negative electrode (cathode): Cu²⁺ + 2e⁻ → Cu [1]. Positive electrode (anode), where oxygen forms: 4OH⁻ → O₂ + 2H₂O + 4e⁻ [1]. Examiner insight: “Redox” needs both halves in (c); explaining only the oxidation of iron earns partial credit at best.

9. (a) Energy saved = 60.0 − 9.0 = 51.0 MJ per kg [1]. Percentage = 51.0 ÷ 60.0 × 100 = 85% [1]. (b) 51.0 × 250 = 12 750 MJ [1]. (c) Ores are limited resources [1]; mining and extraction damage the environment, for example waste rock or carbon dioxide [1]. Examiner insight: In (c) “it is better for the environment” alone is too vague to gain credit; name an effect such as waste rock or carbon dioxide.

10. (a) 4.20 − 2.00 = 2.20 g [1]. (b) MgCO₃ (Mᵣ 84) → MgO (Mᵣ 40) [1]. 4.20 × 40/84 = 2.00 g, matching the result [1]. CaCO₃ (Mᵣ 100) → CaO (Mᵣ 56) would leave 4.20 × 56/100 = 2.35 g, which does not match [1]. (c) Zinc oxide is yellow while hot; this residue stayed white [1]. (d) It would not change mass, because sodium carbonate does not decompose at Bunsen burner temperatures [1]. Examiner insight: A “show that” answer needs every calculated value written down, not just the final 2.00 g.

11. (a) ZnCO₃ + H₂SO₄ → ZnSO₄ + H₂O + CO₂ [1]; the salt is zinc sulfate [1]. (b) Bubble the gas through limewater [1]; the limewater turns cloudy white [1]. (c) Mᵣ ZnCO₃ = 65 + 12 + 48 = 125, so amount = 2.50 ÷ 125 = 0.0200 mol [1]. Ratio ZnCO₃ : CO₂ = 1 : 1, so 0.0200 mol of CO₂ [1]. Volume = 0.0200 × 24 000 = 480 cm³ [1]. Examiner insight: In (c), 24 dm³ is 24 000 cm³; an answer of 0.48 needs the unit dm³.

Where marks are usually lost

• Calling an alloy a compound, or saying an alloy must contain only metals.
• Leaving spectator ions in an ionic equation, or not balancing charge.
• Saying the metal ion is oxidised in a displacement reaction.
• Mixing up phytomining (plants, burning, ash) with bioleaching (bacteria, leachate).
• Writing hydrogen at the cathode when copper ions are present; copper is deposited.
• Treating every carbonate as decomposing in a Bunsen flame.

Next steps

• Metals revision notes
• Metals study guide
• Quantitative chemistry practice questions for the mole steps
• OxfordAQA International GCSE Chemistry hub
• Printable checklist
• Try all free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

OxfordAQA International GCSE Chemistry (9202) specification, Version 6.2, for exams May/June 2018 onwards, published by OxfordAQA. Section 3.3.1 Metals, including 3.3.1.1 The reactivity series and 3.3.1.2 Metal carbonates.