Practice Exercise. A closed steel reaction flask is initially filled with 1.75 mol of nitrogen gas at a pressure of 3.00 atm at 30 °C. After some of the nitrogen gas was allowed to escape, the final pressure

was 1.50 atm at 25 °C. Calculate the mols of nitrogen gas that escaped. ( 0.860 mols )

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.