[SOLVED] Thermodynamics and Gas Properties

This assignment involves solving two thermodynamics problems. The first problem deals with a pressurized air tank that supplies compressed air to an engine. When the engine is not running, the absolute pressure in the tank is 280 bar, and the temperature of the air is 70°C. As the engine starts, the absolute pressure drops to 250 bar, and we are asked to calculate the new temperature of the air in the tank. The second problem involves a piston with an initial absolute pressure of 220 kPa, volume of 0.2 m^3, and temperature of 25°C. When pushed down by a force, the air occupies a third of its original volume while maintaining constant temperature. We are required to find the final absolute pressure in the piston and the mass of air within it.