What Is a Homogenous Mixture?

Typically, the term homogenous mixture is used in chemistry. To fully understand the term as it applies to chemistry, it is necessary to first understand what homogenous means and what constitutes a mixture. Homogenous is derived from the Latin term, homogeneus, meaning same or kind. In defining what constitutes a mixture, a mixture is formed when two or more compounds or elements are combined without the occurrence of chemical bonding or alterations. Used in chemistry, homogenous means having a uniform composition, therefore, a homogenous mixture is one with a uniform mixture of compounds or elements.

Also known as a solution, a homogenous mixture can be viewed under a microscope to verify the even distribution of materials. For example, if a homogenous mixture were split into four parts, each part should contain 25 percent of the total volume of each compound. A homogenous mixture containing one part salt and four parts water, for example, should still have the same ratio of salt to water when divided in half or quarters. Elements in a homogenous mixture are suspended in the solution and do not change distribution as a result of settling.

Aside from the even distribution of compounds and elements, homogenous mixtures also have only one phase, meaning particles stay one size at all times. While the elements or compounds within a mixture do not chemically combine, the suspension of elements is even. By contrast, heterogeneous mixtures have more than one phase and do not evenly distribute components within the mixture. When viewed by the naked eye, the elements within a heterogeneous mixture can be seen as separate from the other elements. Sand mixed into water, for example, is a heterogeneous mixture with two separate, visible phases or particle sizes.

Examples of homogenous mixtures include air with no clouds, simple syrup, corn oil, and white vinegar. Each of these examples are called solutions, with equal distribution of materials and molecule or atom-sized particles. Solutions are formed from solutes and solvents. The solvent is the larger volume, usually water, with solutes being the smaller volume dissolved or otherwise dispersed in the solvent.

Milk and fog are examples of homogenous mixtures known as colloids, characterized by larger particle sizes. Although colloids have larger particles, these mixtures maintain the same even distribution of compounds and elements. Colloids are unique examples of homogenous mixtures because colloids have two phases — dispersal and continuous — based on the size of particles within the mixture. Owing to the two separate phases of a colloid, these mixtures are halfway between a conventional homogenous mixture and a heterogeneous mixture. Particles are not visible to the naked eye like in a heterogeneous mixture, but the mixture does have two separate phases.