Question

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

Answer 1

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.