Diffusion -- What is average distance travelled?

[vegemite]

Homework Statement

Would appreciate any help quite confused on this topic.
If a type of ion has a diffusion coefficient of 10^-8 m^2/s in water. What is average distance traveled after 30 mins?

What sort of graph should you plot in order to easily test validity of r=squarer root-2Dt. How will value of diffusion constant be obtained from such a graph?

Homework Equations

√x=√2Dt

The Attempt at a Solution

I've tried to transpose th equation and failed at transferring the correct units. also I don't know how to visualize it as a graph.

thanks

 

[Chestermiller]

This is the same thing as finding the center of mass. So what is your equation for determining the center of mass?

Chet