A rigid tank containing 0.4 m3 of air at 400 kPa and 30°C is connected by a valve to a pis...

A rigid tank containing 0.4 m3 of air at 400 kPa and 30°C is connected by a valve to a piston-cylinder device with zero clearance. The mass of the piston is such that a pressure of 200 kPa is required to raise the piston. The valve is now opened slightly, and air is allowed to flow into the cylinder until the pressure in the tank drops to 200 kPa. During this process, heat is exchanged with the surroundings such that the entire air remains at 30°C at all times. Determine the heat transfer for this process.