7.2.2 Combustion of Alkenes

All hydrocarbons can combust (burn in oxygen) to release energy.

Complete combustion of alkenes produces carbon dioxide and water, provided there is a plentiful supply of oxygen.

Incomplete combustion of alkenes occurs where oxygen is limited and produces water, carbon monoxide and carbon (soot). This causes a smoky flame.

Functional group

Alkenes have a functional group C=C – the part of the molecule that takes part in reactions. Alkanes, in contrast, do not have a functional group and are less reactive as a result.

Complete combustion of alkenes produces carbon dioxide and water, provided there is a plentiful supply of oxygen.

Here are the equations for the complete combustion of propene:

$$Propene + oxygen → carbon dioxide + water$$ $$C3H6 + 4 12 O2 → 3CO2 + 3H20$$