An insulated piston-cylinder device initially contains 0.2 m3 of R-134a, half (by volume) of which is in

Question:

An insulated piston-cylinder device initially contains 0.2 m3 of R-134a, half (by volume) of which is in the vapor phase. The mass of the piston maintains a constant pressure of 200 kPa inside. A valve is then opened and all the liquid refrigerant is allowed to escape. Determine
(a) The mass of liquid refrigerant in the beginning.
(b) The mass withdrawn.
(c) The entropy generated during the process.