Why is the shape of a catalyst molecule important?

The size and shape of the catalyst pieces is a trade off between the desire to minimize pore diffusion effects in the catalyst particles (requiring small sizes), and pressure drop across the reactor (requiring large particle sizes).

Explanation:

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

the correct answer would be b. amelia, because the particals of gas move really fast (charged particals) and gas also has a lot of room (particals move independently) so the only answer that has both of those is amelia's.