Given #O_2#, #Cl_2#, and Ne, which gas has the fastest rate of diffusion? Slowest? Why?

1 Answer

Neon is the fastest. Chlorine is the slowest. We must assume that all these gases are at the same temperature.


The rate of diffusion is dependent on the molar mass of the gas. Heavier gas particles move more slowly, lighter ones will move faster.

At equal temperatures, all these gases will have the same kinetic energy (KE).

Kinetic energy can be calculated using the following relationship:

KE = #1/2mv^2#
m = mass
v = velocity

So for a lighter gas to have a KE equal to that of a heavier gas, is must be moving faster (higher velocity = v)

For further explanation, please see this video:

Video from: Noel Pauller

Hope this helps!