Use Activity Coefficient From Gamma Input when you need to compute the ionic activity as the activity coefficient times the molar concentration. Enter Activity coefficient and Concentration using the definitions and units below so the result can be reproduced.

Activity coefficient

A finite measured or assumed value.

Concentration

A finite measured or assumed value, expressed in M.

The published tool contract uses this rule: Compute the ionic activity as the activity coefficient times the molar concentration.

Activity

The calculated activity.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.

Retain the original Activity coefficient and Concentration values and their units alongside the result. Mean Ionic Activity is useful when you instead need to compute the mean ionic activity coefficient for a 1:1 electrolyte as the square root of the cation and anion coefficient product. Activity Calculator provides another view by helping you compute thermodynamic activity a = gamma * concentration.

• Mean Ionic Activity

  Compute the mean ionic activity coefficient for a 1:1 electrolyte as the square root of the cation and anion coefficient product.

• Activity Calculator

  Compute thermodynamic activity a = gamma * concentration.

• Activity From Fugacity

  Compute the thermodynamic activity as the ratio of fugacity to the standard pressure of one bar.