At 323 K, the vapor pressures of pure n-hexane and n-heptane are 54.4 and 18.8 kN m2, respectively. Assuming ideality, determine: a) The amount fraction of n-hexane in a solution in equilibrium with a vapour in which the amount fraction of n-hexane is 0.85. b) The molar entropy change when this solution is formed from pure components at 323 K