Fick's first law

Quantitative Aspect of Liquid Phase Diffusion

n 1 dt = 1 2 × S . dx dt × C 1 { n_{1}} over {dt}= {1} over {2} × {S.dx} over {dt}× C_{1}
n 2 dt = 1 2 × S . dx dt × C 2 { n_{2}} over {dt}= {1} over {2} × {S.dx} over {dt}× C_{2}

We put :

n 1 n 2 = dn ; ( C 1 C 2 ) = dC n_1-n_2=dn; (C_1-C_2 )=dC
dn dt = 1 2 × S . dx dt × dC { dn} over {dt}= {1} over {2} × {S.dx} over {dt}× dC

Fick's first law

D = D 0 × S × dC dx D=- D_{0} ×S× {dC} over {dx}
Figure 4: Diffusion shows the liquid phase

Units of the Fick equation

The tables 1 and 2 show the units for Fick's first law

Table 1: represents a molar and mass debit unit.
Table 2: represents a molar and mass flow unit.