Fractional distillation of crude oil

Step 1

The crude oil is heated until it evaporates

Step 2

The vapour then enters the fractionating column, which has a temperature gradient

Step 3

It is hotter at the bottom and cooler at the top

Step 4

The vapour will begin to rise up the fractionating column, each fraction condensing at its respective boiling points

Step 5

Long chain hydrocarbons have high boiling points since longer molecules have stronger intermolecular forces requiring more energy to break down, and so condense at the bottom of the column. Short chain hydrocarbons therefore condense at the top