A piston-cylinder device initially contains 1.2 kg of steam with a volume of 0.2 m3. The mass of the piston is such that it maintains a constant pressure of 1.0 MPa. The cylinder is connected through a valve to a supply line that carries steam at 5.0 MPa and 500 °C. Now the valve is opened and steam is allowed to flow slowly into the cylinder until the volume of the cylinder doubles and the temperature in the cylinder reaches 250 °C, at which point the valve is closed. (a) State the assumptions and write and simplify the mass and energy balance equations. (b) Calculate the work done during the process. (c) Determine the mass of steam that has entered. (d) Calculate the amount of heat transfer.