Answer to Question #173691 in Classical Mechanics for Viccy

Question

Explain diffusion constant

Answer 1

Diffusion constant or Diffusion coefficient:

It is a proportionality constant between the molar flux due to molecular diffusion and the gradient in concentration of species.

In the fick's law, it is the proportionality factor which is represented by D. In the feek's law the mass of the substance dM diffusing in dt time through the surface dF normal to normal to the diffusion direction. Which is proportional to the concentration gradient grad c of this substance.

dM= -D grad c