5. an insulated, rigid tank is divided into two compartments by a frictionless, thermally conducting piston. one compartment initially contains 1 m3 of saturated water vapor at 4 mpa and the other compartment contains 1 m3 of water vapor at 20 mpa, 800°c. the piston is released and equilibrium is attained, with the piston experiencing no change of state. for the water as the system, determine (a) the final pressure, in mpa. (b) the final temperature, in °c. (c) the amount of entropy produced, in kj/k.