As fuels
3 marks · NormalExplain why burning hydrocarbons in a poorly ventilated room can lead to serious health risks. In your answer, refer to the products formed during incomplete combustion.
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Burning hydrocarbons in little air causes incomplete combustion, producing carbon monoxide, which is poisonous and can prevent oxygen from reaching cells, leading to health risks or death.
Must show: mention of carbon monoxide, danger to health, reason oxygen transport is reduced
Common mistakes: referring only to smoke/soot; omitting the mechanism (oxygen transport)
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Marking points
M1 · 1 mark · Recognises incomplete combustion occurs in little air/poor ventilation.
B1 · 1 mark · States carbon monoxide is formed as a result of incomplete combustion.
A1 · 1 mark · Explains carbon monoxide is dangerous as it reduces the blood's ability to carry oxygen, causing health risks/death.
Worked solution
If hydrocarbons are burned in a room with little air, incomplete combustion occurs. This can produce carbon monoxide, a poisonous gas. Carbon monoxide binds strongly to haemoglobin in the blood, reducing its ability to carry oxygen to the body's organs, which can lead to serious health risks or even death.