SC2b Filtration And Crystalisation

Question 1

What do filters do

Answer 1

They can be used to separate some mixtures. They let smaller pieces or liquids through but trap bigger pieces or insoluble substances.

Question 2

Examples of filtration

Answer 2

Cars , vacuum cleaners and air conditioning systems

Question 3

What is a solution

Answer 3

A mixture of solutes ( dissolved substances ) in a liquid called the solvent .

Question 4

How can solutes be seperated

Answer 4

They can be separated in a process called crystallisation . This is when solutes can be separated from a solution by evaporating the solvent leaving the solutes behind

Question 5

What is a saturated solution

Answer 5

A solution that contains the maximum amount of solute that can dissolve in that amount of solute .

Question 6

Filtration and crystallisation in the lab

Answer 6

Fo filter a solution in a lab a filter funnel is lined with filter paper that has fine holes in it. The solvent and solute pass through the fine holes to form the filtrate . Bits of insoluble substances cannot fit through the holes so they leave a residue on the paper. A Bunsen burner is then used to evaporate the filtrate carefully . Care must be taken not to overheat the solution once saturated as hot crystals may spit out . Further heating may cause crystals to change chemically

Question 7

How to reduce of a hazard when doing crystallisation

Answer 7

During crystallisation the risks of spitting can be reduced by wearing eye protection and removing the Bunsen burner before the solution is completely dry.