A Container Is Divided into Two Chambers That Are Separated

A container is divided into two chambers that are separated by a valve.The left chamber contains one mole of a monatomic ideal gas.The right chamber is evacuated.At some instant, the valve is opened and the gas rushes freely into the right chamber.Which one of the following statements concerning this process is true?

A) Work is done by the gas.
B) The temperature of the gas decreases.
C) The change in the entropy of the gas is zero.
D) The walls of the containing vessel must get colder.
E) The change in the internal energy of the gas is zero.