In chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Furthermore, in chemistry, four types of mathematical description can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration. The term concentration can be applied to any kind of chemical mixture, but most frequently it refers to solutes in solutions.

Read more about Concentration:  Qualitative Description, Related Quantities, Dependence On Volume, Table of Concentrations and Related Quantities