A sheet of 0.001" thick BCC iron foil separates a high hydrogen content gas from a low hydrogen content gas at 725 degree C. 8 times 108 H atoms/cm3 are in equilibrium on one side of the foil, and 3 times 104 H atoms/cm3 are in equilibrium on the other. Determine the concentration gradient of hydrogen and the flux of the hydrogen through the foil.