A new containment vessel for nuclear waste is being tested by a group of engineers working for the U.S. Department of Energy. The spherical vessel is made from 50 kg of lead and is pressurized with hot argon. After being filled with the hot argon, the
container is lowered into a wind tunnel where it is cooled for 1 minute. During this cooling the air flow rate through the wind tunnel is 4.0 kg/s.

The air enters the wind tunnel at 27°C and exits at 37°C (all at 1 atm pressure). At the start of the 1 minute cooling cycle the temperature of the vessel and argon is 500°C and the pressure of the argon is 2000 kPa. As the vessel and argon cool, the vessel and the argon are at the same temperature. The volume of the vessel is 0.8 m3. The wind tunnel is well insulated. Neglect the mass of the air inside the wind tunnel. Assume variable (temperature dependent) specific heat for the air and that both the air and argon are ideal gases. Neglect changes in potential and kinetic energy. Find the final temperature and pressure of the argon after the 1 minute cooling
period.