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.

Unsaturated Revision Resources to Ace Your Exams

To explore unsaturated compounds further, you should check out the revision notes on alkenes and practise our exam questions to ensure success. Flashcards on hydrocarbons are also a great way to revise the wider topic of hydrocarbons before an exam. 

Explore our GCSE Chemistry revision resources.