A rigid tank of 0.566 m3 volume contains air at 6.895 bar and 21.1°C. The tank is equipped with a relief valve that opens at a pressure of 8.618 bar and remains open until the pressure drops to 8.274 bar. If a fire causes the valve to operate once as described, determine the air temperature just before the valve opens and the mass of air lost due to the fire. Assume that the temperature of the air remains constant during discharge and air in the tank behaves as an ideal gas.