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 through a 7.8-mm-thick sheet of palladium having an area of 0.80 m^2 at 500°C. Assume a diffusion coefficient of 6.7 x 10^-8 m^2/s, that the concentrations at the high- and low-pressure sides of the plates are 2.8 and 0.72 kg/m^3 of hydrogen per cubic meter of palladium, and that steady-state conditions have been attained.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2