Problem #$1$: $(10)$

Compute the time $[$s$]$ required to pass $1\mathrm{.}35$ milligrams of hydrogen through a $2$ mm thick sheet of palladium having an area of $0\mathrm{.}50m^2$ at $500C.$ Assume a diffusion coefficient of $1\mathrm{.}1{10}^{-8}\frac{m^2}{s},$ that the concentrations at the high and low pressure sides of the plate are $3\mathrm{.}4$ and $0\mathrm{.}7$ kg of hydrogen per cubic meter of palladium, and that steady$-$state conditions have been attained. Make all calculations. Be careful with units.