# diffusion

1. ### Diffusion Coefficient

I know that <r^2> = some function of D. But what I don't know is if it is 2*D*deltat*#of dimensions which would be 4*D*deltat; or would it be 2*D*deltat. The lecture notes say the latter, but I've seen quite a bit of literature saying it is the former. Much appreciation if anyone can help me...
2. ### rate of diffusion

In this problem, you are to find out how much faster helium diffuses than chlorine. To find the rate of diffusion, To find out, you put the square root of the density of the second one over the density of the first one. The density of chlorine is .003214. The density of helium is...