They are methods of seperating mixtures. Filtration seperates insoluble solids from liquids.
Two ways to seperate soluble liquids from solutions - evaporation and crystallisation.
evaporation - pour solution into evaporating dish, heat evaporating dish which will evaporate the liquid and form crystals, repeat until there are only dry crystals remaining.
crystallisation - pour soution into evaporating dish and gently heat, once some solvent has evaporated leave the dish to cool, salt should form crystals as it becomes insoluble in acold highly concentrated solution, filter the crystals and leave them to dry.
Both can be used to separate rock salt
1. grind the mixture to make the salt smaller
2. put the mixture in water to dissolve the salt
3. filter the mixture, the salt will filter but the sand won't
4. evaporate the water so you are left with just the salt (crystallisation can also be used here)
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