Activity coefficients are used to calculate the actual concentration of non-ideal solutions. When two liquids are mixed together in different mole fractions, the mole fractions of their vapors will also be different. The partial pressures of each component is measured in both the liquid and vapor phase. With a knowledge of both mole fractions and partial pressures, we can determine the activity of each component from Raoult's law and Henry's law. The end goal of this problem is to derive and provide a relation between the activity coefficient, partial pressures and mole fraction from both Raoult's law and Henry's law individually.
Most chemistry freshmen (and yes, freshwomen too!) encounter aqueous equilibrium which involves the calculation of equilibrium constants and the all familiar pH. Generally, these involve the use of molarity concentrations but the unit is said to be dimensionless. We all know that if concentrations are used in terms of molarity, the units cannot be disregarded. There is no magic to chemical problems! Units ...
The method of finding activity coefficients from both Raoult's law and Henry's law is given.