The average kinetic energy of gas molecules,
(i) is independent of the nature of gas.
(ii) depends upon the temperature of the gas as 1/2 mC2 = 3/2 kBT, i.e., 1/2 mC2 ∝ T.
(iii) is independent of the volume of the gas.
At absolute zero, r.m.s. velocity of the gas molecules become zero so mean K.E. per molecules of the gas becomes zero at absolute zero.