A hollow sphere of Nickel is suspended inside a closed vessel containing a gaseous mixture of hydrogen and air (yH2 = 0.36) at 100 C and 5 atm total pressure.

The sphere has an external radius of 15 cm and a thickness of 2 mm. It was verified that the concentration is negligible inside the sphere.

Considering DH2-Ni = 1.16 10-8 cm2s, determine the mass flow rate in (kg/s) of H2 by diffusion into the sphere at steady state.