Write four differences between heterogeneous and homogeneous mixtures.

Hint: A Mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.

Complete step by step answer:
Let us first understand what is a mixture.
When two or more substances mix with each other which results in the formation of a Mixture. The result which is formed due to combining of two substances i.e. these substances do not lose their individuality nor are they combined chemically. Mixtures can either be heterogeneous or homogeneous in nature.
The constituents of the mixture can be separated by physical methods.
- What is a Heterogeneous mixture?
A Heterogeneous mixture is a mixture with a non-uniform composition. It's a non-uniform mixture of smaller constituent parts. Heterogeneous mixtures contain multiple parts in multiple phases, but they usually behave as a whole.
- What is a Homogeneous mixture?
A Homogeneous mixture is simply any mixture that is uniform in composition throughout. As long as each substance is mixed in enough to be indistinguishable from the others, it is a Homogeneous mixture. Homogeneous mixtures are also referred to as solutions.

Let us differentiate between Homogeneous and Heterogeneous mixtures!
Homogeneous mixture:
- Homogeneous mixtures have a uniform composition throughout the mixture.
- Components are not visible to the naked eye.
- The whole mixture is in the same phase.
- Particle size is often at atomic or molecular level.
- Components cannot be easily separated.
Example: mixture of alcohol and water.

Heterogeneous mixture:
- Heterogeneous mixtures have a mixed composition which may vary from point to point.
- Components can be seen easily.
- Substances can be of two phases and layers may be separated.
- Heterogeneous mixtures have large particle sizes.
- Components can be separated easily.
Example: mixture of sodium chloride and sand.

Note: The individual substances in a mixture can be separated by using methods like filtration, evaporation, distillation and chromatography.