activity coefficient

Assume that the activity coefficients are all equal to 1.

A similar expression is obtained for the mean activity coefficient.

Activity coefficients in the standard state are, by definition, equal to 1.

In addition, the variable a is the activity coefficient for the component one.

When the activity coefficient is close to one, the substance shows almost ideal behaviour according to Henry's law.

The expressions show that at the limiting activity coefficients are equal.

This can be taken into account using the solute's activity coefficient.

It depends on the ratio of the limiting activity coefficients.

Otherwise conditions must be adjusted so that activity coefficients do not vary much.

In high strength solutions, the quotient of activity coefficients changes very little.

By calculating the mean activity coefficients from them the theory could be tested against experimental data.

Activities can be calculated from concentrations if the activity coefficient are known, but this is rarely the case.

In these solutions the activity coefficient may actually increase with ionic strength.

The model can not describe extrema in the activity coefficient along the concentration range.

Use known or calculated activity coefficients, together with concentrations of reactants.

It is possible in principle to obtain values of the activity coefficients, γ.

See activity coefficient for a derivation of this expression.

When an equilibrium constant value is to be determined, there are three options for dealing with the activity coefficients.

Each activity term can be expressed as the product of a concentration and an activity coefficient.

For the molecule, the activity coefficients are broken down as per the following equation:

Frequently, the fugacity of the pure liquid is used as a reference state when using activity coefficients.

In an ideal electrolyte solution the activity coefficients of all the ions are equal to one.

In this situation the mean activity coefficient is proportional to the square root of the ionic strength.

Note that in general activity coefficients are dimensionless.

For equilibria in solution, activity is the product of concentration and activity coefficient.