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Elements, Compounds and Mixtures

What is Fractional Distillation?

Fractional Distillation is a separation technique that is used
for liquids that dissolve in each other.

Liquids that dissolve in each other are called miscible.
A liquid can be separated from a mixture
of liquids in a solution by fractional distillation.

Distillation showing a Condenser

The solution is heated until it boils.
The liquid with the lowest boiling point boils first
and becomes a vapour (gas). The vapour is cooled
in the condenser until the temperature falls
below the boiling point when it condenses
back into a liquid which is collected in a container.

The collected liquid is called the distillate.
It has been distilled.
The condenser has cold water running through
a jacket around the outside to keep the
temperature below the boiling point of the vapour.

After the liquid with the lowest boiling point has
been collected, the temperature of the remaining mixture
will rise to a new temperature
when the liquid with the next lowest boiling point
will boil and be collected. The process can
be continued to separate all the liquids in the mixture.

Fractional distillation
is used to separate
the components of crude oil
and to separate nitrogen and oxygen from liquid air.

Immiscible liquids are separated using a separating funnel.

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