Find the total vapor pressure at 35 degree C above a solution containing 39.5 g CS_2 and 24.3 g C_2 H_2 O, if the vapor pressures at 35 degree C of pure CS_2 and pure C_2 H_6 O are 332 torr and 645 torr respectively Assume the solution behaves ideally. Determine the mole fraction of CS_2 in the vapor phase.