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22. Separation Of Mixtures
Material: Salt -- Sand -- Kleenex paper -- Paper chromatography -- Food color -- Tooth
picks -- Bottle of water -- White vinegar
Method:
1) A mixture of salt and iron filings can be separated by using a magnet which
will attract the iron and not the salt.
2) A mixture of sand and salt can be separated by adding water to the mixture.
3) Salt will dissolve in the water, sand will not. Filter out the sand using
kleenex paper.
4) Evaporate the salt solution which passes through the paper to get the salt.
5) For separating a mixture of food colours - paper chromatography is used.
Additional experiment:
1) Mix tiny drops of different food colours.
2) With a tooth pick take a little bit of the mixture and place it about one
centimetre from the end of a strip of chromatography paper or try kleenex
paper strip.
3) Hang this in a bottle of water (containing a spoonful of white vinegar) so
that the tip of the paper is just touching the water and let it stand undisturbed.
●
As the water rises in the porous paper, one by one the colors
move up. After sometime all the colours are found at separate
heights.
Explanation:
●
All matter is made up of molecules. Different food colours are
made of different molecules with different weights. Lighter
molecules of colour move up first and the heaviest, last. The
method of separation is called Chromatography.

Diagram of Experiment 22