A rigid tank initially contains 2 kg of superheated water vapor at 500 kPa and 300 °C. The water is now allowed to cool until the temperature drops to 120 °C. Determine (a) the final pressure, (b) the quality at the final state, and (c) the total internal energy change for this process. Also, sketch the process on a T-v diagram with respect to the saturation lines.

A piston-cylinder device initially contains 1 kg saturated liquid water at 220°C. Now heat is transferred to the water until the volume expands quadruple of its initial volume. Eventually, the cylinder contains saturated vapor only. Determine the volume at the final stage. (i) (ii) Determine the final temperature and pressure. (iii) Determine the internal energy change of the water. (iv) Sketch the T-v diagram and include all the related information.