A gas-phase reaction A B takes place in a packed-bed catalytic reactor, where a solid catalyst is used to catalyze the reaction. The feed gas consists of 20 mol% A and 80 mol% inert gas. The reactor operates at a pressure of 1 atm and a temperature of 500 K. The catalyst has a surface area of 500 m2/g and an intrinsic rate constant of 0.1 mol/gcat s. The reactor has a diameter of 10 cm and a length of 2 m, and the catalyst bed occupies 50% of the reactor volume. The feed gas enters the reactor at a flow rate of 2 L/min. Calculate: a) The concentration of A at the reactor inlet and outlet. b) The space velocity (SV) of the reactor.