Separating Mixtures

Separating Mixtures

1. Chromatography

   • Paper chromatography is used to separate mixtures of soluble substances. These are often coloured substances such as food colouring, inks, dyes or plant pigments. Pencil must be used so the ink does not mess up the practical.
   • Steps: 1) Draw a pencil line just above the bottom edge. 2) Add a ink dot. 3) Put the strip into a beaker. 4) Add water to reach the bottom of the paper (Must not touch the ink spot)

2. Crystallisation

   • Crystallisation separates solids that have been dissolved (solutes) in a liquid (solvent)
   • This is done by carefully heating the solution so that the liquid evaparates. This leaves crystals of the solid behind. The crystals Can then be washed with cold water to remove impurities and then dried in an oven.

3. Fractional Distillation

   • Fractional Distillation can be used to separation of a liquid mixture by evaporating the liquid.
   • It can be used to separate crude oil by heating it into a condensing vapour to create a colourless liquid

4. To separate liquids you can use: Fractional Distillation, Chromatography and Crystallisation.