Mixtures and Their Types

A mixture is a material system made up of two or more different substances, which are mixed but not combined chemically.
Mixtures can be either homogeneous (uniformly distributed and often called ‘solutions’) or heterogeneous (not uniformly distributed).
Examples of mixtures include seawater, air, and alloys like bronze or steel.

Separating Mixtures

Various techniques are used for the separation of mixtures, these include filtration, evaporation, distillation, fractional distillation, chromatography, and crystallisation.
Filtration is often used to separate a solid substance from a liquid or gas.
Evaporation is employed to separate a dissolved solid from a solution.
Distillation is used to separate two or more liquids that have different boiling points.
Fractional distillation is used to separate a mixture of liquids into its individual components.
Chromatography is used for the separation of an ink into its individual dyes.
Crystallisation is used to separate a solute from a solution.

Unlike compounds, the substances in a mixture each retain their own chemical properties.
The physical properties of a mixture such as melting point and boiling point may vary, since these properties depend on the proportion of each component present in the mixture.

The composition of a mixture can typically be varied.
Mixtures can be separated into their components by physical methods.
Unlike in pure substances, the parts of a mixture can be ‘seen’ and are easily identified.
The elements in a mixture do not need to be present in set ratios; they can be combined in any proportions.

The substances within a mixture can react with each other under the right conditions, leading to chemical changes.
During these reactions, original substances are converted into new substances, exhibiting different properties from their components.
Energy changes, such as heat generation or absorption, are often associated with these reactions.