How should the rate of diffusion of helium compare to that of sulfur dioxide?

1 Answer
Jun 28, 2017


Graham's law of effusion holds that the relative rate of effusion/diffusion of 2 gases is inversely proportional to the square root of the molecular masses of the two diffusing gases.....

#"rate 1"/"rate 2"=sqrt{"Molecular mass of Gas 1"/"Molecular mass of Gas 2"}#

#("rate" (He))/("rate" (SO_2))=sqrt{(64*g*mol^-1)/(4*g*mol^-1)}#

#("rate" (He))/("rate" (SO_2))={8/2}=4#

And so helium should diffuse/effuse FOUR TIMES as FAST as sulfur dioxide. What is special about the molecular mass of each gas; i.e. why were these 2 gases quoted for the problem?