Difference Between a Heterogeneous & a Homogeneous Mixture

A mixture is a combination of two or more substances.

In chemistry, a mixture is simply two or more substances combined. Chemicals in a mixture do not combine and can be separated back into pure elements. Most substances are mixtures because almost everything, no matter how pure, contains some degree of impurity. Though the chemicals do not combine in a mixture, mixtures can still display different properties than the isolated component substances. There are two main categories of mixtures: homogeneous and heterogeneous.

Homogeneous Mixtures

A homogeneous mixture, with the prefix homo- meaning sameness, is a "pure" substance, or one that has the same chemical makeup at any given point in the mixture. A mixture is considered homogeneous if it appears uniform to the eye. That is, they are made up of atomic-sized particles, too small to see. Homogeneous mixtures are also called solutions. Solutions are made up of at least two substances, with one substance dissolving the others so that the solution appears uniform.

Types of Homogeneous Mixtures

A homogeneous mixture usually consists of water, the solvent, acting as the dissolving agent, and other gases, liquids or solids, the solutes, that become dissolved. Some common homogeneous mixtures include saltwater, carbonated water, air, metal alloys and water vapor. Not only are homogeneous mixtures defined by the substances contained within them but also by the relative amounts of those substances that are present.

Heterogeneous Mixtures

A heterogeneous mixture, the prefix hetero- meaning difference, is a mixture that is visibly made up of different substances, or the same substance in different states. Heterogeneous mixtures are also known as suspensions and consist of particles larger than those in a homogeneous mixture. These particles are visible to the naked eye and can be easily distinguished from one another while in

suspension with other substances.

Types of Heterogeneous Mixtures

A heterogeneous mixture is any mixture where the substances have visible boundaries between one another. Suspensions, such as oil and vinegar, air bubbles in a glass of water and clouds in the air, are all heterogeneous mixtures. Most substances are heterogeneous when observed at sufficiently microscopic distances, however, only mixtures that are visibly separate are called heterogeneous. For instance, mayonnaise actually consists of small particles of oil and water, however, it is considered homogeneous because it appears to be one substance to the naked eye.

References

• University of Tennessee at Memphic, Chemistry Department: Heterogeneous vs Homogeneous