1. A 0.2-m3 rigid tank contains 8 kg of water (in any phase or phases) at 500 kPa. What is the temperature in the tank?
2. Consider a sealed can that is filled with refrigerant-134a at 20°C. Now a leak develops, and the pressure in the can drops to the local atmospheric pressure of 80 kPa. What is the temperature of the refrigerant in the can when the pressure drop is complete?
3. A frictionless piston-cylinder device and a rigid tank each contain 5 kg of helium gas at the same temperature, pressure and volume. Now heat is transferred, and the temperature of both systems is dropped by 12°C. How much extra heat must have been supplied to the helium in the cylinder that is maintained at constant pressure?