Hydrogen gas is allowed to permeate through a thin plastic membrane that is 83 microns thick. concentrations of 0.025 moles/m3 and 0.0025 moles/m3 are maintained on the high and low pressure sides of the membrane, respectively. if the diffusivity of hydrogen gas molecules in the plastic is 4.2x10-8 m2/s, how many moles of hydrogen gas pass through a 6.0 square meter area of the plastic membrane every hour ? hint: we are really computing a flow rate here, rather than a flux. a flow rate is equal to a flux multiplied by an area, and its units are generally count / time.