At equilibrium, the chemical potentials the gas and liquid phases of a solvent in a solution are equal, and for an ideal mixture the following equation holds (x is the mole fraction of the solvent): Hvapour (T,P*) + RTln(P/p+) = µsolution (T,P*) + RTln(x) a) Modify this equation for a real solution by involving the activity coefficient of the solvent in the solution, using a Raoult's law standard state. b) The vapor pressure of H₂O above a solution that is 40% by mass in ammonium sulfate, (NH4)2SO4, at 300K is 21.28 torr. The standard vapor pressure of pure water (P*) is 26.6 torr at this 300K. Calculate the activity and the activity coefficient of water in this solution. c) Are the IMF between the salt and the water attractive or repulsive? Explain your answer.

At equilibrium, the chemical potentials the gas and liquid phases of a solvent in a solution are equal, and for an ideal mixture the following equation holds (x is the mole fraction of the solvent): Hvapour (T,P) + RTln(P/p+) = µsolution (T,P) + RTln(x) a) Modify this equation for a real solution by involving the activity coefficient of the solvent in the solution, using a Raoult's law standard state. b) The vapor pressure of H₂O above a solution that is 40% by mass in ammonium sulfate, (NH4)2SO4, at 300K is 21.28 torr. The standard vapor pressure of pure water (P*) is 26.6 torr at this 300K. Calculate the activity and the activity coefficient of water in this solution. c) Are the IMF between the salt and the water attractive or repulsive? Explain your answer.