Isobutane expands adiabatically in a turbine from 5000 kPa and 250oC to 500 kPa at a rate of 0.7 kgmol/s. If the turbine efficiency is 0.80, what is the power output (in MW) of the turbine

Carbon dioxide gas expands isotherm a turbine from 1 mpa, 500 k at 200 kpa. assuming the ideal gas model and neglecting the kinetic and potential energies, determine the change in entropy, heat transfer and work for each kilogram of co2.