We are separating CO2 from CH4 in a perfectly mixed membrane module using a silicone rubber membrane at 25 C. The permeabilities CO2 and CH4 are 2.710-7 and 8.010-8 cm3 (STP)cm/(cm2 -cmHg-s), respectively. The thickness of the active layer of the membrane is 1.2 m. The feed is with 25 mol% of CO2 and 75 mol% of CH4 at a pressure of 2.0 atm. The permeate pressure is 0.5 atm. Assume gases are ideal. (a) Find the mole fractions of CO2 in the retentate and permeate if the cut =0.3. (b) Find the membrane surface area for part (a) if the feed flow rate is 1.0 mol/s.