The purification of hydrogen gas is possible by diffusion through a thin palladium sheet. Calculate the number of kilograms of hydrogen that pass per hour (in kg/h) through a 3.1-mm thick sheet of palladium having an area of 0.25 m2 at 500°C. Assume a diffusion coefficient of 6.0 x 10-8 m2/s, that the concentrations at the high- and low-pressure sides of the plate are 3.0 and 0.64 kg/m3 (kilogram of hydrogen per cubic meter of palladium), and that steady-state conditions have been attained.