Alkene

What is Alkene?

An unsaturated hydrocarbon whose bonding includes a carbon-carbon double covalent bond, C=C, which is its functional group.

This definition is part of the Organic Chemistry chapter in Cambridge IGCSE Chemistry.

Concepts related to Alkene

• c=c
• unsaturated
• aqueous bromine test

Common mistakes with Alkene

• “The alkene with four carbons is called butene.” Supplement 11.2.3 why it fails With four carbons there is more than one place the double bond can sit, so the name is ambiguous. correct Give the locant: but-1-ene has the C=C between carbons 1 and 2; but-2-ene has it between carbons 2 and 3. Taught in 11.2.
• 3. “The four-carbon alkene is called butene.” Supplement 11.2.3 defect A missing locant where more than one position is possible. why With four carbons the C=C can sit between carbons 1–2 or 2–3, giving two different compounds. The name is ambiguous. repair Add the number: but-1-ene or but-2-ene, choosing the numbering that gives the lower value. transfer Explain why propene needs no locant but propan-2-ol does.