Standard Separation Techniques for Mixtures

COMPOUNDS AND MIXTURES

COMPOUND

A compound is a substance which contains two or more elements chemically combined together. A compound is formed as a result of a chemical change. It is a new substance with entirely different properties from those of substances from which it is formed. For example water is a compound of hydrogen and oxygen chemically combined in the ratio 2:1 by mass respectively. Other examples of compound are sound, limestone, common salt, petrol, kerosene, etc.

MIXTURE

A mixture is made up of two or more substances which can be mixed together, mechanically, in any proportion. It can be said to contain two or more constituents which easily be separated by physical method. Examples are air, soil, well water, tap water, milk, sweat, blood etc.

DIFFERENCES BETWEEN COMPOUNDS AND MIXTURES

EVALUATION:

1. Define and give one example of (a) homogeneous mixture (b) heterogeneous mixture
2. Describe an experiment to show that sea water is a mixture.
3. Explain why air is regarded as a mixture

SEPARATING A MIXTURE OF TWO SOLIDS

The following methods are employed in the separation of a mixture of two solids:

1. Sieving
2. Magnetic separation
3. Sublimation

1.