Knowledge database: Basics: Types of matter

Substances that occur in nature, can be divided into several types. The basic division recognizes two basic types of matter: homogeneous and heterogeneous substances. A homogeneous substance has, in each of its small parts, an equal composition, while heterogeneous matter doesn't have an equal composition. For heterogeneous materials, one could say that they consist of many, mutually separated pieces of different homogeneous substances. In other words, heterogeneous materials are mixtures of different homogenous substances. Thus, a mixture of salt and sugar is not a homogeneous substance, but is a mixture of two homogeneous substances - sugar and salt, which together form a heterogeneous mixture.

On the picture one can se different forms of solutions: On the left one can see a liquid solution, while on the right there is a solid solution (alloy composed of different types of metals).

Homogeneous materials can be further divided into pure substances, which have a specific and constant chemical composition and other properties that remain constant. Such types of matter are known as chemical substances. Another type of homogeneous materials are homogeneous mixtures or solutions, which are actually a mixture of pure substances. A solution of sugar in water can serve as an example. The mentioned solution is homogeneous and consists of two pure substances, water and sugar. It is important to note here that crystalline or solid solutions also exist, such as alloys. For instance, a solution of silver in gold is used for the production of jewelry.