Virial expansion of the excess Gibbs free energy gives geochemically useful values for this quantity for water in terms of the (*) osmotic coefficient and another approximation adds a correction factor of 0.2 or 0.3 times
The Truesdell-Jones equation for this quantity can be simplified to another 'extended' equation whose two constants are 0.51 and 3.3 x 108 ['ten to the eighth'] in mks units. The Setschenow coefficient is a linear scaling parameter for this quantity. SIT theory is used to calculate this quantity where the infinite dilution approximation fails. Virial expansion of the excess Gibbs free energy gives geochemically useful values for this quantity for water in terms of the (*) osmotic coefficient and another approximation adds a correction factor of 0.2 or 0.3 times I. In addition to the Pitzer and Davies equations, the B-dot equation corrects another equation which states that it equals a constant times ion charge squared times the square root of ionic strength, the Debye-Huckel equation. For 10 points, name this quantity, symbolized gamma, which multiplies the concentration of a species to give its effective concentration.
The Truesdell-Jones equation for this quantity can be simplified to another 'extended' equation whose two constants are 0.51 and 3.3 x 108 ['ten to the eighth'] in mks units.
activity coefficient [prompt on activity]