1. Separation Techniques

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

3. Magnetic Attraction
This process is 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
1. 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
A separating funnel can be used to separate two immiscible liquids, such as oil and water.

6. Filtration
This process is used to separate insoluble solids from the liquid in a solid-liquid mixture, e.g. separating sand from a mixture of sand and water.
The insoluble solid that remains on the filter paper is called residue. The liquid that passes through is called the filtrate.

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

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

9. 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.

10. Applications of Evaporation
drying wet clothes
drying hair with a hair-dryer
obtaining common salt from the sea
drying salted fish or vegetables

11. Crystallisation
Crystallisation is a process to obtain a solid that decomposes on heating from its solution.
Sugar can be obtained from sugar solution and copper(II) sulphate crystals can be obtained from copper(II) sulphate solution by the process of crystallisation

12. Distillation
Distillation is a process used to separate a liquid(solvent) from a solid-liquid solution or liquid-liquid solution.
Pure water can be distilled from a soft drinks

13. Distillation

14. Fractional Distillation
This process can be used to separate miscible liquids with different boiling points where the liquid with the lower boiling point will vaporize first
We can use this method to separate crude oil into various useful components.

19. Chromatography
Chromatography is a process used to separate the different components in a liquid or gaseous 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

20. 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.

21. 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.

22. 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.

26. Applications The End 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
The End