For ten points, identify this process , the migration of matter down a concentration gradient.  
One equation predicting the coefficient of this process says it equals Boltzmann's constant times temperature over 6 pi times viscosity times radius. Another law governing this process says that the coefficient of this process equals one third times the mean free path times the mean speed.   By considering a one-dimensional random walk modeling this process, the Einstein-Smoluchowski relation can be derived. The namesake equation of this process shows that the rate of it is proportional to the curvature of the concentration with respect to distance, and may be generalized by accounting for convective flux. The earlier mentioned equations are the Stokes-Einstein equation and Fick's law.  For ten points, identify this process , the migration of matter down a concentration gradient.  
One equation predicting the coefficient of this process says it equals Boltzmann's constant times temperature over 6 pi times viscosity times radius.
{Diffusion}