A gas is stored in an isochoric, refrigerated tank that has V = 5 m³. Initially, the gas inside the tank has T = 15°C and P = 5 bar, while the ambient surroundings are at 25°C and atmospheric pressure. The refrigeration system fails, and the gas inside the tank gradually warms to 25°C.

A. Find the final pressure of the gas, assuming it is an ideal gas.

B. Find the final pressure of the gas, assuming the gas is described by the van der Waals equation of state with a = 8.0 × 10⁵ cm⁶ · bar/mol² and b = 100 cm³/mol.

C. For the cases in parts A and B, how much work was done by the gas on the surroundings?