1. 1
   A marine archaeologist recovers a corroded iron nail and an untarnished gold coin from a centuries-old shipwreck. She wants to explain, using the reactivity series, why the two metals have survived so differently after hundreds of years underwater.

   (a)

   Which metal below sits above iron in the reactivity series?

   [1 mark]

   • ACopper
   • BGold
   • CZinc
   • DSilver

   (b)

   Why has the gold coin remained untarnished after centuries underwater, while the iron nail has corroded heavily?

   [1 mark]

   • AGold is very unreactive and does not readily react with water or oxygen
   • BGold reacts with seawater to form a protective rust layer
   • CIron is less reactive than gold, so it corrodes faster
   • DGold dissolves completely in seawater, so no reaction is visible

   (c)

   Explain, in terms of the reactivity series, why the iron nail has corroded but the gold coin has not.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A mining company is deciding how to extract copper from copper oxide ore and aluminium from aluminium oxide ore, since the two metals require very different extraction methods based on their positions in the reactivity series.

   (a)

   Copper is less reactive than carbon. Which method is most suitable for extracting copper from copper oxide?

   [1 mark]

   • AHeating the ore alone produces copper without any other substance
   • BElectrolysis only
   • CThe copper is found as the pure metal, no extraction is needed
   • DReduction with carbon

   (b)

   Aluminium is more reactive than carbon, so it cannot be extracted from aluminium oxide by reduction with carbon. Which method must be used instead?

   [1 mark]

   • ADisplacement using a less reactive metal
   • BElectrolysis of the molten ore
   • CSimple heating of the ore in air
   • DReduction with hydrogen gas

   (c)

   Write a word equation for the extraction of copper from copper oxide using carbon, and state which substance is reduced in this reaction.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A jewellery restorer removes black tarnish (silver sulfide) from an antique silver spoon using a method involving aluminium foil and a warm salt solution. In this process, aluminium displaces silver from silver sulfide, forming aluminium sulfide and shiny silver metal.

   (a)

   Explain, in terms of reactivity, why aluminium is able to displace silver from silver sulfide.

   [3 marks]

   (b)

   Using the idea of oxidation is loss, reduction is gain (OIL RIG), identify which species is oxidised and which is reduced in this displacement reaction, and write an ionic half equation for each process.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Bronze Age metalworkers extracted copper and tin from their ores by heating them with charcoal (carbon) in a fire, since both metals are less reactive than carbon. In contrast, modern industry extracts aluminium from aluminium oxide using electrolysis, which requires large amounts of electrical energy.

   (a)

   Explain why these two very different extraction methods are each appropriate for the metals concerned, referring to the reactivity series.

   [6 marks]

   (b)

   Evaluate the advantages and disadvantages of using carbon reduction versus electrolysis as extraction methods, considering cost, energy use and environmental impact.

   [6 marks]

   Total for question 4: 12 marks

End of questions