Topic 1 - Filtration and Crystallisation

Question 1

what is filtration used for?

Answer 1

separating an insoluble solid from a liquid

Question 2

how can filtration be used in purification?

Answer 2

solid impurities can be separated out from a reaction mixture

Question 3

what is crystallisation used for?

Answer 3

separating a soluble solid from a solution

Question 4

how does crystallisation work?

Answer 4

when the solution is heated the water evaporates away and crystals start to form. filter the crystals out and leave to dry, giving you a salt.

Question 5

how do you use filtration and crystalisation to separate rock salt?

Answer 5

1. grind the rock salt
2. dissolve in water - the salt dissolves but the sand doesn’t
3. filter - the sand is removed
4. crystalise - getting salt