A mixture is a physical combination of two or more chemicals or substances that are not chemically combined together and can be separated by physical means. The constituents of a mixture retain their individual properties. Examples include:

Mixtures are divided into two forms based on their composition. These are:

1. Homogeneous mixture(solution)
2. Heterogeneous mixture

A homogeneous mixture is a mixture in which the components that make up the mixture are uniformly distributed throughout the mixture.
The constituents of a homogeneous mixture exist in a single phase. A homogeneous mixture is also called a solution. A solution is a mixture of two or more substances (solute) which are uniformly dissolved in another substance called solvent. The components of a solution cannot be easily detected by sight as they are completely mixed together. Homogeneous mixtures can exist in solid, liquid or gaseous state. Examples are:

A heterogeneous mixture is a mixture with a non-uniform composition. The composition varies from one region to another with at least two phases that remain separate from each other, with clearly identifiable properties. The components of heterogeneous mixtures can be detected by sight as they exist in different phases. Heterogeneous mixtures are divided into two:

• Suspensions

  A suspension is defined as a heterogeneous mixture in which the solid particles are spread throughout the liquid without dissolving in it. The particles are not in one phase as in solutions. Examples are:

  • Muddy water
  • Orange juice with pulp
  • Sand in water
  • Chalk powder in water
  • Paint pigments in a solvent
  • Blood cells in plasma
  • Clay in water
  • Clouds (water droplets in air)
  • Particulate matter in air pollution

• Colloids

  Imagine mixing tiny particles, like dust, evenly into water. These particles are too small to see individually but make the
  water look cloudy. This mixture is called a colloid. A colloid is a heterogeneous mixture where tiny particles of one substance are scattered through another substance. The particles are too tiny that they do not settle and cannot be detected by the human eye. Colloids are intermediate between solutions and suspensions. Colloids scatter light which is called Tyndall effect. Examples are:

  • Liquid sols : This is a colloidal mixture of solids (dispersed substance) in liquids (dispersed medium) E.g : protoplasm, starch in water, blood, paint, and pigmented ink.
  • Solid sols: This is a colloidal mixture of solids in solids E.g: Ruby glass, gemstones, coloured glass
  • Aerosols: An aerosol is a suspension
    of fine solid particles or liquid droplets in air or another gas. It is a colloidal mixture of solid in gas or liquid in gas. Examples are: fog or mist, dust, smoke.
  • Emulsion: This is a colloidal mixture of liquid in liquid . Examples: milk, hair cream, oil in water.
  • Gel: This is a colloidal mixture of liquids in solids . E.g cheese, butter
  • Foam: This is a colloidal mixture of
    gas in liquid. example is soap bubbles, white layer of beer.