A mixture consists of two or more elements combined chemically.
Examples of mixtures are air and seawater.
Crystillisation is when crystals are formed from a solution which is evaporated.
Filtration is used to separate insoluble solids from liquids. The mixture is passed through filter paper, which traps the solids and allows the liquid to pass through.
Evaporation is used to separate soluble solids from liquids. The liquid is evaporated, leaving the solid behind.
Distillation is used to separate two liquids with different boiling points, e.g. water and alcohol. It can also be used to separate soluble solids from liquids.
Chromotography is used to separate a mixture of dissolved substances in a solution.
A solution is a mixture of a solute (substance which is dissolved) and a solvent (liquid in which the solute is dissolved), e.g. copper sulfate dissolved in water.
The hotter the solvent, the more solute will dissolve in it.
A concentrated solution has a large amount of solute dissolved in a small amount of solvent. A dilute solution has a small amount of solute dissolved in a large amount of solute.
A saturated solution is one which has the maximum possible amount of dissolved solute at that temperature.
A dilute solution can be made concentrated by adding more solute or evaporating off some of the solvent. A concentrated solution can be made more dilute by adding more solvent.
When a saturated solution is cooled to a lower temperature, crystals of the solute form. This is known as crystallisation. For example, when a concentrated solution of copper sulfate in water is cooled, copper sulfate crystals form.