When a-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

Furthermore, the values of D0 and Qd for this diffusion system are 1.4 ? 10-7 m²/s and 13,400 J/mol, respectively. Consider a thin iron membrane 1 mm thick that is at 250?C. Compute the diffusion flux through this membrane if the hydrogen pressure on one side of the membrane is 0.15 MPa (1.48 atm), and on the other side 7.5 MPa (74atm).

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27.2 kJ /mol RT 1.34 x 10-2,PH, (5.14) exp CH