Definitions for "Activity coefficient"
A measure of the extent to which substances, on dissolving in water, form charged ions or associate to form multiple molecules; the amount dissolved influences colligative effects, such as equilibrium freezing point depression of solution drops and reaction rates in solution.
a factor, which relates the activity to the concentration of a species in solution, such that: Ax = FxCx (where: Ax = Activity of the species x; Fx = Activity coefficient of the species x; Cx = Concentration of the species x). The activity coefficient is dependent on the ionic strength of the solution (ions of similar size and charge have similar activity coefficients). It becomes progressively lower as the ionic strength increases, due to inter-ionic interactions. The activity coefficient for any ion in solution can be calculated using the Debye-Huckel equation.
measures the activity of ions with each other in an electrolyte (ion-containing) solution. Ions can complex with each other and also with water.