A cylindrical reactor of radius 0.1 m and height 1 m is filled with catalyst particles of diameter 2 mm. The reactor is used for a gas-phase catalytic reaction, in which the reactants A and B are converted to products C and D with a rate constant of 0.02 m3/(kgcat.s). The reactants A and B are fed into the reactor at a total flow rate of 0.1 m3/s, with a concentration of 2 kg/m3 each. The reactor operates at a pressure of 2 atm and a temperature of 500 K. Calculate the following: a) The number of catalyst particles in the reactor. b) The mass of the catalyst in the reactor.