The mean activity coefficient g± of K2SO4 is defined by the equation:
where nw is the amount of water, ns is the amount of salt and n is the number of ions resulting from dissociating 1 mol of salt.
Activity coefficients
| The figure to the
right shows the mean ionic activity coefficient of potassium
sulfate at 10°C, calculated
with the Extended UNIQUAC model.
The mean activity coefficient g± of K2SO4 is defined by the equation:
|
|
| The osmotic
coefficient is a measure for the activity of water in a solution. The
osmotic coefficient is defined by the equation
where nw is the amount of water, ns is the amount of salt and n is the number of ions resulting from dissociating 1 mol of salt. |
|
Thermal properties
| The heat of dilution
(from molality m) to infinite dilution is the enthalpy change per mol salt when a solution
of molality m is diluted to infinite dilution.
The heat of dilution to infinite dilution is the excess enthalpy relative to the infinitely diluted solution. |
 |
| The (integral) heat
of solution is the enthalpy change per mol salt when an amount of
crystalline salt is dissolved in pure water. The heat of solution is
dependent on the concentration of the resulting solution.
The heat of solution is the excess enthalpy relative to pure water and the pure electrolyte in its standard state. |
 |
| The apparent molal
heat capacity of a salt is the heat capacity of a solution of one mol of
the salt minus the heat capacity of the corresponding amount of pure
water.
The defining equation for the
apparent molal heat capacity (
Cp is the
heat capacity of the solution. nw is the amount of
water, ns the amount of salt and |
 |
)
is:
is the heat capacity of pure water