Suppose that a perfectly insulating box has two chambers inside of it each with a volume of $0\mathrm{.}35$ 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 $300$ K and a pressure of $0\mathrm{.}90$ atm. The chamber on the right is evacuated so that it contain 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 between the final and initial states of the gas.