Review Conceptual Example as background for this problem. It is possible to convert Fick€™s law into a form that is useful when the concentration is zero at one end of the diffusion channel (C1 = 0 in Figure a).
(a) Noting that AL is the volume V of the channel and that m/V is the average concentration of solute in the channel, show that Fick€™s law becomes t = L2/(2D). This form of Fick€™s law can be used to estimate the time required for the first solute molecules to traverse the channel.
(b) A bottle of perfume is opened in a room where convection currents are absent. Assuming that the diffusion constant for perfume in air is 1.0 × 10-5 m2/s, estimate the minimum time required for the perfume to be smelled 2.5 cmaway.

Cross-sectional area A Higher concentration 02 Lower concentration Ci Solute mass Flow Cross-sectional area A Higher temperature Lower temperature 71 Heat flow