Consider a rigid, insulated box containing 0.400 mole of He(g) at 20.0oC and 1.00 atm in one compartment and 0.600 mole of N2(g) at 100.0oC and 2.00 atm in the other compartment. These compartments are connected by a partition that transmits heat. What is the final temperature in the box at thermal equilibrium? [For He(g), Cv=12.5 J K-1 mol-1; for N2(g), Cv=20.7 JK-1mol-1]