Chemical reactions of the alkenes
4 marks · NormalThis question is about reactions of propene (C3H6).
Explain why propene is classified as an unsaturated hydrocarbon.
Write a word equation for the addition reaction of propene with hydrogen.
Describe what is formed when propene burns in a plentiful supply of air.
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(a) Because it contains a C=C double bond (not maximum hydrogens).
(b) Propene + hydrogen → propane
(c) Propene reacts with oxygen to form carbon dioxide and water.
Common mistakes: Incorrect combustion products; Missing the mention of C=C bond for unsaturation
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Marking points
B1 (a) · 1 mark · Explains unsaturated means contains double bond or not maximum hydrogens.
B2 (b) · 1 mark · Correct word equation: propene + hydrogen → propane.
B3 (c) · 1 mark · Correctly states that carbon dioxide is formed.
B4 (c) · 1 mark · Correctly states that water is formed.
Worked solution
a) Propene is unsaturated because it contains a C=C double bond.
b) Propene + hydrogen → propane
c) When propene burns in a plentiful supply of air, it forms carbon dioxide and water.