A rigid tank has a volume of 60 liters and initially contains a two-phase liquid-vapor mixture of H2O at a pressure of 15 bars and a quality of 20%. As the tank contents are heated, a pressure-regulating valve keeps the pressure constant in the tank by allowing saturated vapor to escape. Heating continues until no liquid remains in the tank. Neglecting kinetic and potential energy effects, determine: (a) The amount of heat transfer, in kJ and (b) The mass of vapor that escapes, in kg.