A rigid, 10 m³ vessel initially contains 100 kg of water/ steam at P = 2 bar. 10 kilograms of steam at P = 5 bar and T = 300°C is gradually added to the vessel. During the same time period, heat exchange occurs with the surroundings. The final water/steam mixture is at P = 3 bar.

A. What fraction of the initial contents of the vessel were in the vapor phase?

B. What fraction of the final contents of the vessel are in the vapor phase?

C. How much heat was added or removed?