Submarines change their depth by adding or removing air from rigid ballast tanks, thereby displacing seawater in the tanks. Consider a submarine that has a 700-m3 air-ballast tank originally partially filled with 100 m3 of air at 1650 kPa and 15°C. For the submarine to surface, air at 1650 kPa and 20°C is pumped into the ballast tank until it is entirely filled with air. The seawater leaves the tank at 15°C. Presume that air is added to the tank in such a way that the temperature and pressure of the air in the tank remain constant. Determine the final mass of the air in the ballast tank under this condition. Also determine the total heat transfer while the tank is being filled in this manner. The gas constant of air is R = 0.287 kPa·m3/kg·K. The specific heats of air at room temperature are cP = 1.005 kJ/kg·K and cv = 0.718 kJ/kg·K. The specific volume of water is taken 0.001 m3/kg.