A 0.25-m3 insulated piston€“cylinder device initially contains 0.7 kg of air at 20°C. At this state, the piston is free to move. Now air at 500 kPa and 70°C is allowed to enter the cylinder from a supply line until the volume increases by 50 percent. Using constant specific heats at room temperature, determine
(a) The final temperature,
(b) The amount of mass that has entered,
(c) The work done, and
(d) The entropy generation.

Air 0.25 m3 0.7 kg 20C Air 500 kPa 70C