The following first-order, gas-phase catalytic reaction is conduced in a fixed-bed reactor: A B The rate constant is given by: -38,000 5.74 x 1013 exp RT where the units of Rare in cal mol-' K-and Temperature is in Kelvin. The feed consists of pure A at 1.0 atm at 630K and a molar flowrate of 0.5 mol s-1. The catalyst is a cylindrical shaped pellet with a radius of 0.35 cm and a length of 0.5 cm. The catlyst pellet density is 0.84 g cm-", and the reactor bed density is 0.52 g cm-". At 630K, the diffusivity in the pellet is 1.40 x 10-3 cm? s-!. The reactor operates isothermally and without a pressure drop. Part 1 For the case where diffusion to the pellet surface is infinitely fast (i.e., the surface concentration is equal to the bulk concentration, calculate the mass of catalyst required to achieve 90% conversion of A) Part 2 For the case where the mass transfer coefficient to the external particle surface is 3.75 cm/s, calculate the mass of catalyst required to achieve 90% conversion of A. For this example, you may either apply the flux boundary condition at the catalyst surface or solve the external mass transfer problem separately to find the surface concentration as a function of bulk concentration and apply that surface concentration as your boundary condition