= [3] A piston-cylinder device contains 0.05 kg of steam at 1 MPa and 450C. Steam now expands to a final state of 200 kPa and 175C, doing work. Heat losses from the system to the surroundings are estimated to be 2 kJ during this process. Assuming the surroundings to be at To = 25C and Po 100 kPa, determine (a) the exergy of the steam at the initial and the final states, (b) the exergy change of the steam, (c) the exergy destroyed, and (d) the second-law efficiency for the process.