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In chemistry, separation of mixtures is the separation of the elements of a
mixture. There are many principles that can be applied and they each have their
strengths and weaknesses.
Processes
The main processes for separation of mixtures in chemistry are:
- Decantation - used when the mixture consists of substances of different
densities. The less dense substances is carefully poured off of the more dense
one.
- Filtration - used when one substance is a liquid and the other a solid or
when one of the substances is soluble in a solvent and the other is not.
- Centrifugation - used when the substances have very similar
densities, or when one of the substances consists of very fine particles suspended in a liquid.
- Distillation - used for mixtures of liquids with different boiling
points, or for a solid dissolved in a liquid.
- Chromatography used to separate different dyes or pigments. A
solvent travels through paper by capillary action and carries the
pigments with it. Different pigments are deposited at different places on the paper depending on how much they like the solvent
compared to how much they like to stick to the paper.
- Electrophoresis Organic molecules, such as protein are placed in a gel. A voltage is applied and the molecules move through the gel because they are charged. The gel restricts the motion so that different proteins will make different amounts of
progress in any given time.
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