- Flux is the movement of particles per time (through a given area).
- In diffusion, individual particles are moving at random, and net movement is a result of more particles moving from high to low concentrations than are moving from low to high, thus, (Fick’s First Law)
- Fick’s First Law shares the same form as several other transport equations.
- D (the diffusion coefficient) has units of m2 s-1 or cm2 s-1, and is NOT equal to the speed at which an individual particle moves.
Learning Outcomes
You should now be able to:
- Explain the linear relationship between the rate of movement of a substance and its concentration gradient (Fick’s First Law).
- Measure the rate of movement of a substance from one area to another as a function of the concentration gradient and the diffusion coefficient for that substance in the medium.
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