Gas X has a mass of 28.02 amu and gas Y has a mass of 32 amu. Which gas will diffuse faster?

1 Answer
Aug 19, 2016

The two gases will almost diffuse at the same speed.

Explanation:

The root mean square velocity (U_(rms)) of a gas is found by:

U_(rms)=sqrt((3RT)/(MM))

where, MM is the molar mass of the gas.

If you have two gases, X and Y, the ratio between their U_(rms) can be determined by:

(U_X)/(U_Y)=sqrt((MM_Y)/(MM_X))

=>(U_X)/(U_Y)=sqrt((32)/(28.02))=1.068~=1.1 ("2 significant figures")

Therefore, the two gases will almost diffuse at the same speed.