Define mixture. Why air is a mixture not a compound? Give four reasons. [5 MARKS]
Definition : 1 Mark
Reasons : 1 Mark each
A mixture is a material system made up of two or more different substances which are mixed but are not combined chemically. A mixture refers to the physical combination of two or more substances on which the identities are retained and are mixed in the form of solutions, suspensions, and colloids.
Air is a mixture for the following reasons:
i. Air does not have a fixed composition. Its composition varies from place to place.
ii. The components of air can be separated by a physical method such as fractional distillation of liquid air.
iii. Liquid air does not have a definite boiling point.
iv. We can prepare air artificially by mixing the various components of air in the same proportions in which they occur at a place. This is a physical process because no energy changes occur.