Molar concentration

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Molar concentration, or molarity, or simply concentration, is a term in physical chemistry. It measures the concentration of a solution or mixture.

In chemistry, the molar concentration, c_i is defined as the amount of a constituent n_i (usually measured in moles – hence the name) divided by the volume of the mixture V:[1]

c_i = \frac {n_i}{V}

The volume V in the definition c_i = n_i/V refers to the volume of the solution, not the volume of the solvent. One litre of a solution usually contains either slightly more or slightly less than 1 litre of solvent because the process of dissolution causes volume of liquid to increase or decrease.

The reciprocal quantity represents the dilution (volume) which can appear in Ostwald's law of dilution.

References[change | change source]

  1. International Union of Pure and Applied Chemistry. Amount concentration, c. Compendium of chemical terminology, internet edition. [1]