I only need part b

A typical composition of a natural gas is 0.5% He, 17.0% N2, 76.5% CH4 and 6.0% higher hydrocarbons. The membrane proposed to separate helium has a thickness of 2.54x10cm and the permeabilities are P'A= 60x100cm (STP).cm/(s.cm .cm Hg), P's = 3.0x10-40, and Pc = 1.5x10-10. It is assumed that the higher hydrocarbons are essentially non-permeable (P'o =0). The feed flow rate is 2.0x105 cm (STP)/s. The feed pressure pn = 500cmHg and the permeate pressure p = 20cmHg. a) For a fraction permeated of 0.2, calculate the permeate composition, the reject composition, and the membrane area using the complete mixing model. b) Use the permeate from part a) as feed to a completely mixed second stage. The pressure pi SOOcmHg and p = 20cmHg. For a fraction permeated of 0.20, calculate the permeate composition and the membrane area