Add excess water to the mixture in a beaker and stir well to ensure the solid has completely dissolved.
Filter the mixture. Collect solid as residue, solution as the filtrate.
Evaporation to Dryness
Heat solution in an evaporating dish until all the water has evaporated/boiled off.
Solid is left on the evaporating dish.
Crystallisation
Heat solution until saturation (Usually when 1/3 of liquid is left).
Crystals are formed when cooled. Collect crystals.
Filter the mixture to get crystals.
Wash crystals with small amount of distilled water and air-dry / pat-dry with pieces of filter paper.
Sublimation
Heat mixture in evaporating dish.
Collect the sublimate on a cold surface, like an inverted filter funnel.
Examples of solids that sublime on heating:
Iodine
Ammonium chloride
Carbon dioxide
Simple Distillation
The solution boils in the round bottom flask.
Boiling chips are added to ensure smooth boiling and prevents bumping of the liquid
The thermometer measures the boiling point of the vapour before it enters the condenser.
In the condenser, the vapour condenses and changes from gaseous to liquid state. Water enters from the bottom and exits from the top of the condenser to ensure that the condenser is fully filled and that the bottom of the condenser is the coolest to prevent/reduce loss of vapour/gas.
Solvent collected is known as the distillate.
The solid is left at the bottom of the flask.
Fractional Distillation
A liquid of higher boiling point will condense at the fractionating column and fall back into the flask. A liquid with lower boiling point will be able to pass through the fractionating column. This ensure separation of liquids according to their boiling points. This ensures separation of liquids according to their boiling points.
The fractionating column increases the surface area for the condensation of the vapour, making separation of the vapours more effective.
Lower boiling point liquid is collected first as distillate.
Eg.: alcohol and water, crude oil
Separating funnel
Denser liquid is collected first from the tap below.
Reverse osmosis
High pressure is used to force impure water through a membrane which has millions of tiny holes/pores. Only water molecules can pass through the pores, leaving solute particles behind.