02 A catalytic cracking of ethane (1) to ethylene (2) and hydrogen (3), is presented in equation 1. C2H6C2H4 + H2 Eq.1 (1) (2) (3) The bulk gas composition is 60% mole C2H6 and 20% mole each of CH4 and H2. The mole fraction of the gases at the catalyst surface is: y = 0.4, y2 = 0.3 and y3 = 0.3. Diffusion of ethane to the catalyst surface occurs through a stagnant gas film of thickness 1.5 mm and the products diffuse back. Knowing that the temperature is 720C, the pressure is 2.0 atm, and the gas constant is 82.1 atm.cm3/mol.C). i- Estimate the diffusivities of the species (D12 and D13) using the binary diffusion correlation and the data given in the appendix. Also estimate the diffusivity of ethane in the gas mixture (Dum) at the catalyst surface [15 marks] ii- Derive an equation for the diffusion flux (NA) in this particular system [15 marks] iii- Calculate the flux of ethane through the gas film [10 marks] 03) An open cylindrical test tube, 1.5 cm in diameter and 12 cm long, has 0.4 g camphor in it. The pressure is atmospheric and the temperature is 20C. Knowing that the sublimation pressure of camphor at this temperature is 97.5 mm Hg, the diffusion coefficient of camphor through a stagnant layer of air is (DAB = 7.6x107m/sec), camphor molecular weight and density are (Mw= 152.23 g/gmol, p = 990 kg/m?) and the gas constant is R= 8.205x10-5 m.atm/(mol.K). i- Derive an equation for the diffusion flux (NA) in this particular system ii- Derive an equation for estimating the time required for camphor sublimation iii- How long will it take for the camphor to disappear? [10 marks] [10 marks] [10 marks]