Question

Two different gases are stored in separate closed containers. If both gases have a temperature of 50°C, which statement is true?
The thermal energies of gas molecules in the two containers are unrelated.
The gas molecules in both containers will absorb heat from the surroundings.
The molecules in one gas will transfer energy to the molecules in the other gas.
The gas molecules in both containers have the same average kinetic energy.

Answer 1

The gas molecules in both containers have the same average kinetic energy.

Reason: For an ideal gas the average translational kinetic energy per molecule depends only on temperature: ⟨KE⟩ = (3/2)kT (or (3/2)RT per mole). So at the same temperature both gases have the same average kinetic energy, though their average speeds can differ if their molecular masses differ.