$1\mathrm{.}3$ Calculate the rate of diffusion of acetic acid, A$,$ across a film of nondiffusing water, B at $17C.$ The film has a thickness of $1mm$ and the concentration of acetic acid changes from $9\%(\frac{w}{w})$ on one side of the film to $3\%(\frac{w}{w})$ on the other. The diffusivity of acetic acid in the solution is $9\mathrm{.}5{10}^{-10}\frac{m^2}{s}.$ The density of the $9\%$ acid solution is $1012k\frac{g}{m^3}$ while that of the $3\%$ acid solution is $1003\mathrm{.}2k\frac{g}{m^3}.$ The molecular weight of the acetic acid is $60k\frac{g}{k}$mol.

Hint: Use the data to calculate a mean value for the bulk solution concentration, $c.$