Fractional distillation

In a nutshell

Fractional distillation is used to separate out a mixture of liquids based on their different boiling points.

Fractional distillation

Fractional distillation can be used to separate crude oil, this produces many useful products such as petrol and diesel. The stages of fractional distillation are explained below.

Science; Pure and impure substances; KS3 Year 7; Fractional distillation

1.	Flame
2.	Mixture
3.	Flask
4.	Hottest part of column
5.	Fractionating column with glass rods
6.	Coolest part of the column
7.	Thermometer
8.	Cooling water going out
9.	Condensor
10.	Cooling water going in
11/12.	Test tubes with fractions

procedure

1.	Put the mixture in a flask.
2.	Attach a fractionating column and condenser to the flask as shown in the diagram.
3.	Heat up the flask, gradually. Different liquids have different boiling points which means they will evaporate off at different temperatures as the flask heats up and the liquids boil.
4.	Liquid with the lowest boiling point will evaporate first. When the boiling point is reached the liquid will turn into a gas and rise to the top of the column then condense out via the condenser.
5.	Liquids with a higher boiling point will not reach the top of the column and will condense back down into the flask.
6.	Once the first liquid has been collected, raise the temperature until the next liquid reaches the top of the column.
7.	Collect the different liquids in different test tubes.