describe the process of fractional distillation
-crude oil is heated until all hydrocarbons evaporate in gas/vapour
-crude oil is pumped into a column with a temperature gradient of cool at the top and hot at the bottom
-longer hydrocarbons(chains) have higher boiling points so condense and drain out the bottom early on
-shorter hydrocarbons(chains) have lower boiling points so they condense at the top but drain out much later on
-crude oil mixture is seperated into different fraction depending on boiling points