Cracking

Long chain hydrocarbons are not very flammable so don’t make good fuels. To solve this, we convert long chain hydrocarbons into short chain hydrocarbons through the process of cracking.

In cracking, not only do we create short chain hydrocarbons, but we also make alkenes.

There are two ways we can carry out cracking:

Catalytic cracking

Using a high temperature and a catalysts to speed up the reaction.

Steam cracking

Using a high temperate and steam.

Alkenes

Alkenes have a double covalent bond between carbons. They are used to make polymers and the starting material for other chemicals.

Alkenes are more reactive than alkanes and therefore we can test for them.

We test for alkenes using bromine water, which is orange. If an alkene is present, the bromine water will turn colourless after we shake it.