Despite their presence in all fields of chemistry, chemical mixtures cannot be represented by any formula. This is because they contain two or more distinct chemical components that are either heterogeneous or homogeneous. The substances in a mixture, no matter how closely they have intermingled, have no firm chemical interaction or bonding between or among themselves.

A heterogeneous mixture combines substances which have distinct and different phases, such as ice cubes and water. In homogenous mixtures, the atoms or molecules of the ingredients are interspersed with each other to form a single phase, as in a mixture of gases.

There are four types of mixtures which are either heterogeneous or homogeneous. The first type of mixture is called a "solution," in which chemical components (whether gas, solid, or liquid) combine to form a single-phase, homogeneous mixture whose components are evenly distributed. An "azeotropic" mixture is one...