When -iron is subjected to an atmosphere of hydrogen gas, the concentration of hydrogen in the iron, CH (in weight percent), is a function of hydrogen pressure, pH2 (in MPa), and absolute temperature (T) according to CH=1.34102pH2exp(27.2kJ/molRT) Furthermore, the values of D0 and Qd for this diffusion system are 1.8 10^-7 m2/s and 11 kJ/mol, respectively. Consider a thin iron membrane 1.7-mm thick that is at 226C. Calculate the diffusion flux [in kg/(m2-s)] through this membrane if the hydrogen pressure on one side of the membrane is 0.2 MPa, and on the other side 6.4 MPa, given that the density of iron is 7.87 g/cm3.

(a) What is the concentration of hydrogen at the low-pressure (or B) side in wt%?

(b) What is the concentration of hydrogen at the high-pressure (or A) side in wt%?

(c) What is the concentration of hydrogen at the B face in kilograms of H per cubic meter?

(d) What is the concentration of hydrogen at the A face in kilograms of H per cubic meter?

(e) What is the concentration gradient (C/x) in kg/m4?

(f) Calculate the diffusion coefficient, D, in m2/s at the specified temperature.

(g) Compute the diffusion flux in kg/m2-s.