Chemical reactions of the alkenes
2 marks · EasyExplain why alkenes burn to produce carbon dioxide and water when heated in oxygen.
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Must show: alkenes_contain_C_and_H, combustion_reacts_with_oxygen_to_form_CO2_and_H2O
Also accept: Hydrocarbons react with oxygen to form carbon dioxide and water.
Common mistakes: Saying only water is formed.
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Marking points
B1 · 1 mark · States that alkenes are hydrocarbons containing carbon and hydrogen.
B1 · 1 mark · Explains that combustion in oxygen forms carbon dioxide and water.
Worked solution
Alkenes are hydrocarbons so they contain only carbon and hydrogen. When burnt in oxygen, the carbon forms carbon dioxide and the hydrogen forms water.