Suppose that a perfectly insulating box has two chambers inside of it, each with a volume of 0.35 L. The chambers are connected by a stopcock valve. When the valve is closed, no gas passes between the chambers. Initially, when the valve is closed, the chamber on the left is filled with gas at a temperature of 325 K and a pressure of 0.90 atm. The chamber on the right is evacuated so that it contains no gas.

When the stopcock valve is opened, the gas redistributes to fill both chambers, eventually reaching a new equilibrium state.

Determine the change in internal energy Δ between the final and the initial states of the gas.