$2\mathrm{.}23$ The vapor pressure of solid naphthalene at $23C$ is $0\mathrm{.}07mmHg.$ A naphthalene sphere of diameter $1cm$ is suspended in still air. How long is required for the sphere to lose $87\mathrm{.}5\%$ of its initial mass? Use ${}_{\text{s}\text{o}\text{l}\text{i}\text{d}}=1150k\frac{g}{m^3},M_{w,\text{n}\text{a}\text{p}\text{h}}=128\frac{g}{g}*mol,$ and $D_{\text{n}\text{a}\text{p}\text{h}\frac{?}{?}\text{a}\text{i}\text{r}}=8{10}^{-6}\frac{m^2}{s}.$

Solve using shell mass balances and Fick's Law