Extracting metals from their ores
4 marks · NormalThe list shows three metals in order of reactivity:
Gold Iron Aluminium
Which metal is most likely to be found in the Earth's crust as the uncombined element? Explain your answer.
State one common ore of iron.
Describe the method used to extract iron from its ore.
Explain why aluminium must be extracted by a different method than iron.
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(a) Gold, because it is the least reactive metal and is found as native metal.
(b) Hematite or magnetite.
(c) By reduction of the iron ore using carbon in a blast furnace.
(d) Aluminium is more reactive than carbon and cannot be reduced by carbon, so must be extracted by electrolysis.
Common mistakes: Confusing carbon reduction and electrolysis; Naming the wrong ore
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Marking points
B1 (a) · 1 mark · Identifies gold and gives correct reason relating to low reactivity/found as native.
B1 (b) · 1 mark · Names a correct iron ore (e.g., hematite, magnetite).
B1 (c) · 1 mark · Correctly describes extraction by reduction with carbon.
B1 (d) · 1 mark · Explains why aluminium requires electrolysis, linked to its position in the reactivity series.
Worked solution
a) Gold, because it is unreactive and can be found as the element.
b) Haematite (Fe2O3) or magnetite (Fe3O4).
c) Iron is extracted from its ore by reduction with carbon in a blast furnace.
d) Aluminium is more reactive than carbon, so cannot be reduced by carbon and must be extracted by electrolysis.