The air in a piston–cylinder device initially has a volume of 0.2 m³ at 400 kPa and 120° C. The air expands in a reversible process from 400 kPa to 150 kPa at a constant temperature of 120° C. The air temperature in the cylinder is maintained constant during this process as a result of heat transfer to the surrounding medium at 250° C. Determine:

A. The P–V work during the process.

B. The change in entropy of the ideal gas during this process.

C. The change in entropy of the surroundings during this process.

D. The change in entropy of the world (system + surroundings) during this process.