A container with rigid walls is covered with perfectly insulating material. The container is divided into two parts by a partition. One part contains a gas while the other is fully evacuated (vacuum). The partition is suddenly removed. The gas rushes to fill the entire volume and comes to equilibrium after a little time. If the gas is not ideal,
A. the initial internal energy of the gas equals its final internal energy
B. the initial temperature of the gas equals its final temperature
C. the initial pressure of the gas equals its final pressure
D. the initial entropy of the gas equals its final entropy
