Unsaturated - GCSE Chemistry Definition

What does unsaturated mean?

In GCSE Chemistry, unsaturated describes a molecule with at least one double (or triple) bond between carbon atoms. This means that alkenes are unsaturated compounds due to their carbon-carbon double bond.

Unsaturated hydrocarbons like ethene and propene are important in the production of polymers / plastics and other synthetic materials.

Essential unsaturated compounds

Each exam board requires knowledge of different specific unsaturated compounds:

*there are different possible structures (isomers) of butene and pentene

Testing for unsaturated compounds

The carbon-carbon double bond makes unsaturated compounds such alkenes chemically reactive. Bromine water, Br₂ (aq), is an orange-brown solution that is used to test for unsaturated compounds. In the presense of carbon-carbon double bonds, bromine water becomes colourless.