1. Separation Techniques
Text by Mrs Teo
Video clips taken from school video repository

2. The Different Separation Techniques are as follows:
Magnetic attraction
Filtration
Evaporation
Crystallisation
Distillation
Chromatography
Note: The physical method used will depend on the nature of the constituents.

3. Magnetic Attraction
used to separate magnetic materials, e.g. iron, steel, nickel, cobalt from non-magnetic ones in a mixture
e.g. separating iron filings from sulphur powder.

4. Applications of Magnetic Attraction
Electromagnets are used to remove steel and iron scrap at the junk-yard.
2. In hospitals, magnets are often used to remove iron splinters from a patient’s eyes.

5. Using a Separating Funnel
can be used to separate two
immiscible liquids, such as oil
and water.

6. Filtration used to separate an insoluble solid from
(i) a liquid in a solid-liquid mixture
e.g. sand from a mixture of sand and water or
(ii) a soluble solid
e.g. calcium carbonate from mixture of it
and copper(II) sulphate.

7. Filtration insoluble solid that remains on the filter paper - residue.
liquid that passes through- filtrate.

8. Applications of Filtration
hair in our nostrils
trap the dust particles that we breathe in and allow only clean air to pass through
air filters in air conditioners
remove solid impurities from air
oil and air filters in cars
remove solid impurities found in engine oil and air

9. Evaporation to dryness
used to separate a dissolved solid that does not decompose on heating from a solution,
e.g. common salt from a salt solution.

10. Procedure of Evaporating a Solution
1. Pour the solution into an evaporating dish.
2. Heat the solution to dryness to evaporate away the solvent, leaving behind the solute.
3. Make the Bunsen flame smaller when almost all the solvent has been evaporated away to reduce spitting.

11. Applications of Evaporation
drying wet clothes
drying hair with a hair-dryer
obtaining common salt from the sea

12. Crystallisation
process to obtain a solid that decomposes on heating from its solution.
e.g. sugar from sugar solution and copper(II) sulphate crystals from copper(II) sulphate solution

13. Distillation
process used to separate a liquid (solvent) from a solid-liquid solution or liquid-liquid solution.
e.g. pure water can be distilled from soft drinks

14. Distillation

15. Fractional Distillation
process can be used to separate miscible liquids with different boiling points
liquid with lower boiling point will vaporize first
e.g. to separate alcohol and water

16. Industrial Applications of Fractional Distillation
oil refineries - separating the various components of crude oil or petroleum
industries supplying oxygen to hospitals, shipyards, etc – separating the components of air

17. Fractional Distillation

20. Paper Chromatography
process used to separate the different components in a liquid mixture For example it can be used
1. to separate the different coloured components that make up black ink
2.to detect tiny amounts of drugs or certain other chemicals in urine samples.

21. Paper Chromatography
1. Apply a small but concentrated spot of the solution on a piece of chromatography paper.
2. Suspend the chromatography paper in a beaker or boiling tube of solvent with the spot above the level of the solvent.

22. Paper Chromatography
3. Separation takes place because some components of the liquid mixture travel at a faster pace than other components on the paper or any other absorbent material.

23. Paper Chromatography
3. As the solvent travels up the paper, the mixture is separated into its respective components.
A chromatogram of the separated components is obtained.

27. Applications analysing ink dyes for forgery cases
analysing food dyes to ensure that
only permitted colourings are used
in foodstuffs
checking whether pesticides on vegetables exceed safe levels
detecting trace levels of drugs in
urine samples

28. The End

29. ACE Suggestion
1. Production of whisky by distillation of barley mash

30. ACE Suggestion
2. Commercial Production of sodium chloride by: (i) Mining
(ii) Evaporation of sea water