Activity coefficients are themselves functions of concentration as the amount of inter-ionic interaction increases as the concentration of the electrolyte increases.
42.
In chemical engineering the Margules Gibbs free energy model for liquid mixtures is better known as the Margules activity or activity coefficient model.
43.
Activity is defined as the product of the activity coefficients and the concentrations of Ca 2 + and SO 4 2-ions.
44.
However, chemists have never been able to give up the idea of single ion activities, and by implication single ion activity coefficients.
45.
For the i ^ { \ mathrm { th } } molecule, the activity coefficients are broken down as per the following equation:
46.
Although the model is old it has the characteristic feature to describe extrema in the activity coefficient, which modern models like Wilson cannot.
47.
In dilute solutions, the Nernst equation can be expressed directly in the terms of concentrations ( since activity coefficients are close to unity ).
48.
In highly concentrated solutions, simple approximations such as the Henderson Hasselbalch equation are no longer valid due to the variations of the activity coefficients.
49.
[A ] is the concentration of reagent A, etc . It is possible in principle to obtain values of the activity coefficients, ?.
50.
The theoretical equation can be tested by combining the calculated single-ion activity coefficients to give mean values which can be compared to experimental values.
