Uses of aluminium
4 marks · NormalThe diagram below shows a cross-section of a wire made from aluminium.
What is the chemical name of the oxide layer that forms on aluminium?
State how this oxide layer protects aluminium from corrosion.
Explain one practical use of aluminium that relies on its resistance to corrosion.
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(a) aluminium oxide
(b) It acts as a barrier to prevent oxygen or water from reaching the aluminium metal.
(c) Making bodies of airplanes because the oxide layer protects the aluminium from environmental corrosion, increasing durability.
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Marking points
B1 (a) · 1 mark · Correctly names aluminium oxide as the protective layer.
B2 (b) · 1 mark · Correctly states that the oxide layer acts as a barrier or prevents further reaction.
M1 (c) · 1 mark · Identifies an appropriate practical use (e.g. airplane bodies, outdoor structures, cooking pans, cables).
A1 (c) · 1 mark · Explains how resistance to corrosion is relevant to that use.
Worked solution
a) Aluminium oxide is the chemical name of the protective layer.
b) This oxide layer prevents oxygen and water from reaching the metal, so it stops further corrosion.
c) A practical use is for airplane bodies. The corrosion-resistant property means the aluminium does not rust, so the planes are less likely to suffer damage from the elements.