Filtration and Evaporation

Rock salt is a mixture of salt and sand.

Salt and sand are both compounds but because the salt is soluble in water and the sand isn't, the two can be separated using the following methods:

 

Simple Distillation

Simple distillation is used to separate a mixture of a liquid and a solid, for example ink.

(1) The liquid is heated and boils off.

(2) The vapour is cooled by cold water, condensed and collected leaving the solid behind.

This can be used to purify sea water or tap water.

 

Fractional Distillation

Fractional distillation is used for separating a mixture of liquids.

(1) The mixture of liquids are heated and each boil off at their own temperature.

(2) The vapour passes up through a fractionating column.

(3) The vapour is cooled by cold water, condensed and collected.

Fractional distillation is used on a large scale to separate the components of crude oil, because the different hydrocarbons have different boiling points (Distillation of crude oil).