Substances

A substance describes matter where the chemical composition, physical, and chemical properties are the same throughout the sample. If the properties change across a sample, it is not one substance, but a mixture of substances.

Substances can be further characterized by their composition to be elements, molecules, or compounds.

Figure 1 - A, B, and C are all substances. A is a monatomic element. B is a molecule and an element. C is a compound.