A porous activated carbon solid has a BET surface area of 1250 m/g and a pore volume of 0.25 cm/g. Assuming the pores are cylindrical, estimate the average pore size of the catalyst. Compare your value to the molecular diameters of benzene (~0.51 nm) and naphthalene (~0.72 nm) and speculate on the impact that pore size will have on the diffusion of these reactants within the catalyst particle. A porous catalyst has a pore volume of 0.4 cm/g and a solid density of 2.5 g/cm. Calculate the particle porosity.