Extraction and Uses of Metals
5 marks · EasyZinc and iron are both important metals obtained from ores.
State what an ore is.
Name an unreactive metal that is often found native (uncombined) in the Earth's crust.
Explain why carbon can be used to extract iron from its ore, but not aluminium.
Zinc can be extracted by first roasting zinc sulfide in air. Write a word equation for this reaction.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) A rock containing enough of a metal compound to make extraction worthwhile.
(b) Gold · must show gold
(c) Carbon can reduce iron oxide because iron is less reactive than carbon, so carbon can remove the oxygen from iron oxide. Aluminium is more reactive than carbon, so carbon cannot reduce aluminium oxide. · must show iron below carbon, aluminium above carbon, carbon reduction only for metals below carbon
(d) zinc sulfide + oxygen → zinc oxide + sulfur dioxide · must show zinc sulfide + oxygen → zinc oxide + sulfur dioxide
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies that an ore is a rock containing enough of the metal compound for extraction.
B1 (b) · 1 mark · Names gold as an unreactive metal found native (accept also 'silver' or 'copper').
M1 (c) · 1 mark · States iron is less reactive than carbon, so can be reduced by carbon (or explains extraction by reduction with carbon only possible for metals below carbon).
M1 (c) · 1 mark · States aluminium is more reactive than carbon, so cannot be reduced by carbon (must compare to carbon).
B1 (d) · 1 mark · Gives correct word equation for roasting zinc sulfide: zinc sulfide + oxygen → zinc oxide + sulfur dioxide (allow correct formulas if clearly word equation).
Worked solution
a) An ore is a rock that contains enough of a metal compound to make extraction worthwhile.
b) Gold is an example of an unreactive metal found native in the Earth's crust.
c) Iron is less reactive than carbon, so carbon can remove oxygen from iron oxide by reduction. Aluminium is more reactive than carbon, so carbon cannot reduce aluminium oxide and cannot be extracted this way.
d) Word equation: zinc sulfide + oxygen → zinc oxide + sulfur dioxide