Gas molecules confined in a container collide with each other in a completely random manner and exchange energy and momentum during the collisions. These collisions cause the speeds and/or kinetic energies of the molecules to form a special distribution—the Maxwell-Boltzmann distribution. The speed distribution is a bell-shaped curve with a peak at the most probable speed.
Formula : Most probable speed The average thermal velocity is
Formula : Average speed The table below shows the average thermal velocity of selected gases at 20°C.
Table : Molar mass and average thermal velocity of various gases
