Crude oil is a black sticky substance. Hidden in it are many different substances that have essential everyday uses.
Petrol, diesel, tar and many other substances that play very important roles in our everyday lives are found in crude oil.
These substances are known as hydrocarbons:-
Fractional distillation is used to separate crude oil into fractions. A fraction is a group of hydrocarbons all with boiling points within a specific range.
Because each fraction has its own boiling point, when the crude oil is heated each fraction will boil at different temperatures and leave the crude oil mixture as a gas. This allows them to be separated and collected.
This is done in a fractionating column...
As you go up the fractionating column, the hydrocarbon molecules get smaller and have: