Uses of aluminium
5 marks · HardAluminium has several important uses in everyday life.
State two uses of aluminium and, for each, explain which property of aluminium (or its alloys) makes it suitable for that use.
Explain why aluminium is used for overhead power cables, even though it is not as strong as steel.
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(a) — · must show One valid use of aluminium, Correct matching property for use (e.g. low density, corrosion resistance, electrical conductivity, thermal conductivity, strength when alloyed), Second valid use of aluminium, Correct property for the second use
(b) Aluminium is much less dense than steel, so it is lighter and suitable for overhead power cables. · must show Mentions lower density or lighter weight than steel
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Marking points
B1 (a) · 1 mark · States a valid use of aluminium (e.g. aeroplane bodies, cooking pans, food packaging, power cables).
B2 (a) · 1 mark · Gives the correct property of aluminium or its alloy relevant to the use given (e.g. low density for aeroplanes, corrosion resistance for food packaging).
B3 (a) · 1 mark · States a second, different use of aluminium.
B4 (a) · 1 mark · Gives the correct property for the second use.
B5 (b) · 1 mark · Explains that aluminium is used for overhead cables because it is much less dense (lighter) than steel.
Worked solution
(a) Examples:
Aeroplane bodies — property: aluminium alloys have low density (are lightweight) and good strength.
Cooking pans — property: aluminium is a good conductor of heat.
Food packaging — property: aluminium resists corrosion, so it protects food.
(b) Aluminium is used for overhead power cables because it is less dense than steel, so it is much lighter making it easier to support high above the ground.