This set practises ranking metals from evidence, choosing extraction methods, reading corrosion results, explaining alloys and weighing recycling. The questions get harder as you go. All data is invented for practice.
Write each answer on paper first, including units. The final section sends each kind of error back to the right lesson.
Part A: Displacement and ranking
Q1. Invented metals P, Q and R were tested with solutions of their sulfates. P displaced Q and R. Q displaced R. R displaced neither P nor Q, and Q did not displace P. Put the metals in order of reactivity.
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P displaced both others, so it is the most reactive. Q displaced only R. R displaced nothing. Order: P > Q > R.
Q2. Magnesium is added to copper(II) sulfate solution. Write the ionic equation and say which species is oxidised.
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Mg + Cu²⁺ → Mg²⁺ + Cu. Charges: 2+ on each side. Magnesium loses electrons, so magnesium is oxidised and copper ions are reduced.
Q3. Copper is added to zinc sulfate solution and nothing happens. Explain why.
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Copper is less reactive than zinc, so it cannot take zinc’s place in the compound. Only a more reactive metal can displace a less reactive one.
Q4. 6.5 g of zinc is added to an excess of copper(II) sulfate solution. Zn + CuSO₄ → ZnSO₄ + Cu. Ar: Zn 65, Cu 64. Find the mass of copper formed.
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Moles of Zn = 6.5 ÷ 65 = 0.10 mol. The ratio Zn : Cu is 1 : 1, so moles of Cu = 0.10 mol. Mass = 0.10 × 64 = 6.4 g.
Part B: Extraction
Q5. Using a series in which carbon sits between aluminium and zinc, name a suitable extraction approach for calcium, iron and gold, with one reason each.
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Calcium: electrolysis, because it is above carbon and carbon cannot reduce its oxide. Iron: reduction with carbon or carbon monoxide, because it is below carbon. Gold: found uncombined, because it is very unreactive.
Q6. Fe₂O₃ + 3CO → 2Fe + 3CO₂. Ar: Fe 56, O 16. What mass of iron can be made from 160 g of iron(III) oxide?
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Mr of Fe₂O₃ = 2 × 56 + 3 × 16 = 160. Moles = 160 ÷ 160 = 1.0 mol. Ratio Fe₂O₃ : Fe = 1 : 2, so 2.0 mol Fe. Mass = 2.0 × 56 = 112 g.
Q7. Aluminium oxide is electrolysed: 2Al₂O₃ → 4Al + 3O₂. Ar: Al 27, O 16. What mass of aluminium is formed from 102 g of aluminium oxide?
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Mr of Al₂O₃ = 2 × 27 + 3 × 16 = 102. Moles = 102 ÷ 102 = 1.0 mol. Ratio Al₂O₃ : Al = 2 : 4 = 1 : 2, so 2.0 mol Al. Mass = 2.0 × 27 = 54 g.
Part C: Corrosion, alloys and recycling
Q8. Invented results: tube E has a nail in boiled water under a layer of oil, and no rust forms. Tube F has a nail in tap water open to the air, and rust forms. Tube G has a nail wrapped in zinc strip in tap water open to the air, and the nail does not rust. What do E and F show, and what does G show?
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E and F differ in dissolved oxygen, so together they show that oxygen is needed. G shows the iron is protected by the more reactive zinc, which corrodes in its place.
Q9. A tin-plated steel can is scratched through to the steel. Explain why rusting is likely to start, and how zinc coating would differ.
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Tin is less reactive than iron and only acts as a barrier. Once scratched, oxygen and water reach the steel. Zinc is more reactive than iron, so it protects the steel even when scratched.
Q10. An invented alloy is 92% metal X and 8% metal Y by mass. Find the mass of Y in 350 g, then explain why the alloy is harder than pure X.
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Mass of Y = 0.08 × 350 = 28 g, and X is 322 g, which gives 350 g in total. Atoms of Y are a different size from atoms of X and disrupt the layers, so the layers slide less easily and the alloy is harder.
Q11. Invented figures: extracting a metal uses 150 units of energy per tonne. Recycling uses 18 units, and collecting and sorting add 22 units. Find the net saving and the percentage saving, then write a one-sentence judgement.
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Recycling total = 18 + 22 = 40 units. Net saving = 150 − 40 = 110 units. Percentage = 110 ÷ 150 × 100 = 73.3%. Judgement: in this case recycling saves a large share of the energy even after collection and sorting, so it is favoured on energy grounds.
If you got these wrong
- Q1 to Q4: ranking or reading the table backwards. Go to ordering metals from displacement observations. Underline the metal added before writing a conclusion.
- Q4, Q6, Q7: the mole steps. Use the mole and equation-ratio tutor to check the ratio, and the equation balance reasoning trainer for the equation. Revisit relative masses and amounts if needed.
- Q5 to Q7: choosing or explaining the method. Go to relating extraction to reactivity.
- Q8 and Q9: conclusions from controls, or protection. Go to explaining corrosion conditions.
- Q10: alloy reasoning or percentages. Go to comparing an alloy with a pure metal.
- Q11: weighing benefit and cost. Go to interpreting a recycling trade-off.
Keep a short note of each slip in the mistake log and retest queue, and return to the module overview when a whole part feels uncertain. Students who want a teacher to read each line of working can look at online one-to-one Chemistry tuition.