Separation techniques
Filtration
This technique is used to separate an insoluble solid from a liquid. It can be used to obtain a product that is free from unreacted chemicals, by-productA product from a side reaction which is formed during the creation of another product. or solventThe liquid in which the solute dissolves to form a solution..
Image caption, Separating insoluble solids
1. One beaker contains a mixture of solid and liquid, the other contains a funnel with filter paper
Image caption, 2. The solid and liquid mixture is poured into the filter funnel
Image caption, 3. The liquid drips through the filter paper but the solid particles are caught in the filter paper
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Evaporation
One way to separate a soluble solid from its solution is to make crystals. This involves evaporationThe process in which a liquid changes state and turns into a gas. the solution to a much smaller volume and then leaving it to cool. As the solution cools, crystals form, and these can be obtained by filtration.
Simple distillation
Distillation separates a liquid from a solution. For example, water can be separated from salty water by simple distillation. This method works because the water evaporates from the solution, but is then cooled and condensationA change of state in which gas becomes liquid by cooling. in a condenser and collected in a separate container. The salt does not evaporate and so it stays behind.
Separating a liquid from a solution
Image caption, Simple distillation
1. Salty water is heated
Image caption, 2. The water vapour cools in the condenser and drips into a beaker
Image caption, 3. The water has condensed and is now in the beaker, the salt stays behind
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