Ethanol burns in air
2 marks · EasyEthanol burns in air to produce two products. Describe, in terms of substances, what is formed when ethanol undergoes complete combustion, and explain why these products are formed.
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Also accept: Names or correct formulae for carbon dioxide and water; Explanation using the idea of carbon and hydrogen in ethanol combining with oxygen
Common mistakes: Incorrectly stating carbon monoxide or soot as products of complete combustion; Omission of either water or carbon dioxide
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Marking points
B1 · 1 mark · States the two correct products: carbon dioxide and water (either by name or formula).
B2 · 1 mark · Gives a correct reason for their formation: ethanol contains carbon and hydrogen which react with oxygen in the air.
Worked solution
When ethanol burns completely in air, it reacts with oxygen to form carbon dioxide and water:
The carbon atoms from ethanol combine with oxygen to form carbon dioxide, and the hydrogen atoms combine with oxygen to form water.