Mixtures and Methods of Separation

In our daily life we come across many substances that are made up of more than one component. These substances are called mixtures. For example, air, soil, seawater, and tea are all mixtures. A mixture is formed when two or more elements or compounds are combined together in any proportion without undergoing a chemical change. The substances present in a mixture retain their own properties and can usually be separated by simple physical methods.

Scientists and people in everyday life use different methods of separation to separate useful substances from mixtures or to remove unwanted materials. Some common methods include winnowing, sieving, sedimentation, decantation, filtration, evaporation, crystallization, sublimation, centrifugation, and distillation. These techniques are based on differences in properties such as size, weight, solubility, and boiling point.