A rigid tank, whose volume is 0.5 m
, initially containing ammonia at 20C, 1.5 bar, is connected by a valve to a large supply line carrying ammonia at 12 bar, 60C. The valve is opened only long enough to fill the tank with additional ammonia, bringing the total mass of ammonia in the tank to 143.36 kg. Finally, the tank holds a two-phase liquid-vapor mixture at 20c. Ignoring kinetic and potential energy effects, determine the heat transfer between the tank contents and the surroundings, in kJ.