A rigid, sealed titanium cylinder contains a fixed mass of argon gas. The cylinder is moved from a sub-zero scientific outpost at -35degC into a heated calibration chamber at 65degC.
Assuming the thermal expansion of the titanium cylinder is negligible, which of the following properties of the argon gas remains completely unchanged?
The density of the gas inside the cylinder
The total internal energy of the gas
The mean square speed of the argon atoms
The average force exerted per unit area on the inner walls of the cylinder