A rigid tank of volume V is subdivided into two parts with volumes V1 = V/3 and V2 = 2V/3 using a rigid partition. Volume V1 contains an ideal gas at 800◦C and pressure P1 while volume V2 is completely evacuated. Now the partition between the two volumes is removed, upon which the ideal gas expands into the entire tank. Heat is then applied to the gas until its pressure becomes equal to its initial pressure P1.

Determine the final temperature of the gas.