Separation techniques

Mixtures are not chemically bonded so can be seperating using filtration, crystallisation, simple distillation, fraction distillation and chromatography.

Can be used to separate different dyes in ink:
1) Draw a pencil line near the bottom of a sheet of filter paper.
2) Add a spot of the ink to the line and place in the beaker of a solvent. Make sure the ink does not touch the solvent.
3) place the kid on the top of the container.
4) Each different dye in the ink will move at a diffent rate and so will separate out. Each dye will form a spot in a different place.
5) When the solvent has nearly reached the top of the paper, take it out the beaker to dry.

The point the solvent has reached is called the solvent front.
Rf value = distance moved by the compound / distance moved by the solute.

Separates a liquid from a solution.
1) The solution is heated and the part of the solution with the lowest boiling point will evaporate.
2) The vapour cools, condenses in the condenser and is collected in a beaker.

You can use this to get pure water from sea water.
It only works if the two substances have very different boiling points.

Used to separated a mixture of liquids and is how crude oil is seperated in a refinery

1) Put a fractional coloumn over the top of a flask containing your mixture and add heat.
2) Each liquid will evaporate at a different temperature, depending on their boiling points.
3) Because the coloumn is cooler towards the top, liquids with a higher boiling point will condense back down if the temperature is not high enough.
4) When the first liquid has been collected you turn up the temperature and collect the next one in a different boiling tube.