The permeability coefficient of a type of small gas molecule in a polymer is dependent on absolute temperature according to the following equation:

where PM0and Qp are constants for a given gas-polymer pair. Consider the diffusion of hydrogen through a poly(dimethyl siloxane) (PDMSO) sheet 20 mm thick. The hydrogen pressures at the two faces are 10 kPa and 1 kPa, which are maintained constant. Compute the diffusion flux [in (cm3 STP)/cm2 -s] at 350 K. For this diffusion system
PM0=1.45 × 10ˆ’8 (cm3 STP)(cm)/cm2-s-Pa
Qp = 13.7 kJ/mol
Also, assume a condition of steady state diffusion

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