[2] The irreversible, first-order reaction (A B) was conducted at 500 K and 125 kPa using spherical catalyst pellets (diameter d, = 80 mm). The reaction feed consists of 10%

A and 90% N2. Assume that the external mass transfer resistance is negligible compared to the internal mass transfer resistance. The effective diffusivity of A (D.) is 0.8 m' sec", the pellet density (p.) is1667 kg m', and the surface area (S.) is 100 m g'. The observed reaction rate constant (k') was12x10 m (a) Calculate the actual overall reaction rate (unit = mol secg'). (8 pt) (b) Calculate the concentration of A (unit = mol m) where the distance from the center of thecatalyst pellet is 20 mm. (7 pt)