Reactions of metals with water
3 marks · NormalExplain, using the reactivity series, why copper is suitable for use in water pipes but zinc is not.
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Copper does not react with water or steam because it is below hydrogen in the reactivity series, so it does not corrode or release hydrogen gas. Zinc, above hydrogen, can react with steam to form zinc oxide and hydrogen, making it unsuitable for water pipes.
Also accept: Accept concise answers that identify copper’s lack of reaction and link it to its use
Common mistakes: Thinking copper does react with water; Confusing reactivity order: placing copper above zinc
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Marking points
M1 · 1 mark · States that copper does not react with water/steam because it is below hydrogen in reactivity series.
M2 · 1 mark · Links lack of reaction to pipe usefulness: copper does not corrode/form gas.
A1 · 1 mark · States zinc is above hydrogen and can react with steam (not cold water), thus not suitable.
Worked solution
Copper is below hydrogen in the reactivity series so does not react with water or steam (1 mark). This makes it suitable for water pipes because it will not corrode or release hydrogen gas (1 mark). Zinc is above hydrogen and can react with steam to produce zinc oxide and hydrogen (1 mark), making it unsuitable for this use.