Separation Techniques 

Mixture and Pure Substance

A mixture is a substance that consists of two or more elements or compounds that are mixed together but that do NOT chemically join together. A mixture is therefore not pure because it contains different particles.

Mixture can homogenous or heterogenous

Separation Techniques

Mixtures are separated into their component parts by trying to find differences in their physical properties such as size, colour, shape, magnetism, solubility, density and boiling point.

Separation techniques are:

• Manual sorting like hand sorting.

• Magnetic Sorting- this method can only be used when one component is magnetic and the other is not.

• Chromatography- it is a separation technique used in separating components in a liquid mixture. It involves the sample being dissolved in a particular liquid or gas called a solvent.

  • Paper chromatography uses filter paper and a liquid solvent such as water. the sample (e.g. an ink spot) is placed on a spot of paper and the paper is carefully dipped into a solvent. As the solvent rises up the paper, the molecules of the different ink colours which are different in size travel at different speeds up the piece of paper and the various colours separate.

• Separating Funnel

• ~~Distillation~~- distillation is a process that can be used to separate a pure liquid from a mixture of liquids when the liquids have different boiling points and are miscible (don’t mix together) the mixture is heated in a flask and the liquid with the lowest boiling point will evaporate first. The water vapour passes through the Liebig Condenser.