Steam at 800 kPa, 600°C enters a steady flow turbine and leaves at 100 kPa. The steam undergoes an expansion process through the turbine, does work in the amount of 600 kJ/kg, and loses 50 kJ/kg of energy by heat transfer to the surroundings.

(a) Determine the exit temperature of the steam, in °C.

(b) If the surroundings have a temperature of 25°, what is the total entropy change for this process?

(c) Comment on your answer to part (b). Is this process possible?

(d) Determine the maximum work that the steam could have done and calculate the isentropic efficiency of the process.