A piston-cylinder device contains 1.0 kg of liquid water and 0.01 kg of water vapor (steam) in equilibrium at 7 bars. The pressure is held constant and heat is added until the temperature reaches 280 C. a) Determine the initial temperature [C] of the mixture. b) Determine the change in volume [m3]. c) Plot the process on a P-v and P-T state diagram.