MIXTURE SEPARATION

Separation Techniques

Deal with the separation of mixtures to enhance purity of substances
This is very important because most substances are needed in their pure state.

Some Types of Separation Techniques

Filtration
This is a technique used to separate mixtures of an insoluble solid and a liquid.



Examples of Mixtures You Can Separate Using Filtration
- Sand and water
- Broken glass and water
- Chalk suspensions and water

Chromatography

Chromatography is the separation technique used to separate soluble substances using a media and a solvent.
It is mostly applied in identifying mixtures that are coloured or pigments.

Types of Chromatography
- Radial chromatography
- Ascending chromatography
- Descending chromatography

Radial Chromatography
In this type of chromatography, as the pigment separates, the different colours move outwards.

Radial Chromatogram



Ascending Chromatography
The solvent moves upwards on the separating media




Descending Chromatography
The solvent moves downwards on the separating media.




Distillation

This is the separation technique where two miscible liquids are separated.
It is made possible due to the fact that each liquid has its unique boiling point.

Types of Distillation
- Simple distillation
- Fractional distillation

Simple Distillation
This is a technique used to separate a mixture of a soluble substance and a solvent.
E.g salt and water



Fractional distillation

This is the technique used to separate a mixture of two miscible liquids with different boiling points.E.g water and ethanol
The boiling point for water is 100 while for ethanol it is 78.

Fractional Distillation Demonstration




Questions
1. What is a mixture?
2. Give three ways of separating a mixture.
3. What kind of mixtures can you separate using the filtration method?
4. Give an example of a mixture you can separate using the fractional distillation method.


Answers
1. It is a substance made up of two or more substances which are physically combined.
2. Filtration, Chromatography and Distillation.
3. Mixtures of an insoluble substance and a liquid.
4. Ethanol and water.