Uses of aluminium
4 marks · NormalA student compares aluminium and iron for use in outdoor bicycle frames.
Suggest one property of aluminium that makes it especially good for outdoor frames.
Name the substance that makes aluminium resistant to corrosion.
Describe how this substance forms and protects the aluminium beneath.
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) Resistant to corrosion (does not rust), or low density
(b) Aluminium oxide
(c) It forms when aluminium reacts with oxygen in the air, producing a thin but very strong layer that stops water and air from reaching the metal, so it prevents corrosion.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies a correct property (resistance to corrosion or low density).
B2 (b) · 1 mark · Correctly names aluminium oxide.
M1 (c) · 1 mark · Describes the formation of the oxide layer by reaction with air.
A1 (c) · 1 mark · Explains the layer's role as a barrier to prevent corrosion.
Worked solution
a) Aluminium resists corrosion, making it suitable for outdoor use.
b) The protective substance is aluminium oxide.
c) Aluminium reacts with oxygen to form a thin, strong aluminium oxide layer. This layer prevents air and water from reaching the metal underneath, stopping corrosion.