Crude oil and it's fractions

Crude oil is a fossil fuel. It is a complex mixture of many different kinds of hydrocarbons molecules.

Hydrocarbons
Hydrocarbons are a group of compounds containing only hydrogen and carbon atoms. Each hydrocarbon molecule consists of a chain of carbon atoms surrounded by hydrogen atoms. All the atoms in each molecule are chemically joined together.

Fractional distilation
Crude oil contains a mixture of different hydricarbons molecules. This mixture isn't really useful. Gas, petrol, and heating oil are more useful fractions. Each fraction is a simpler mixture than crude oil.

Each fraction obtained from crude oil contains a mixture of a few different hydrocarbons. Each fraction has differetn properties and different uses