A pressurised gas mixture of 65.0mol% methane and 35.0mol% propane is expanded over a turbine to generate electricity. The pressure and temperature at the inlet to the turbine are 40.1 bar(gauge) and 384K, respectively. At the outlet of the turbine, the gauge pressure is 0.600 bar, and the temperature is 307K. The atmospheric pressure at the plant is 90.0kPa. a) Assume that the van der Waals equation of state is accurate enough to predict the PVT behaviour of the gas mixture and develop the following applicable equation for residual enthalpy: HR=RT(Z1)va b) Calculate the molar volume of the gas at the inlet (Vin) and outlet (Vout) of the turbine. c) Calculate the molar energy (kJ/mol) extracted by the turbine. (12)