- Unsaturated hydrocarbons.
- Made by cracking long chained alkanes.
unsturated - one pair of arbon atoms are joined by a double covalent bond (C=C)
Alkenes from C → C4:
- C2H4 ethene
- C3H6 propene
The general formula for an alkene is:
- Alkenes are more reactive than Alkanes due to the C=C bond.
Types of reactions that alkene undergo is called addition (with bromide water) -
- Ethene + Bromine water → 1,2 dibromo ethane
- Propene + Bromine water → 1,2 dibromo propane
- Alkanes do not react with bromine water so this can be used to test for an alkene.
orange / brown → colourless