its Mass transfer question please i need the full solution of this question asap

2. A thin plastic membrane separates hydrogen from air. The molar concentrations of hydrogen in the membrane at the inner and outer surfaces are determined to be 0.045 and 0.002kmol/m3, respectively. The binary diffusion coefficient of hydrogen in plastic at the operation temperature is 5.31010m2/s. Determine the mass flow rate of hydrogen by diffusion through the membrane under steady conditions if the thickness of the membrane is (a) 2mm and (b) 0.5mm