|  | 
If one poison molecule walking randomly exists in
this volume, how long will it take to this poison molecule to
hit the small surface of the catalyst ? | 
This volume contain 6.02 1023 molecules, as whe have 2,9 109 collisions/second onto the small surface of catalyst.
for one molecule we will have
  2.9 109 /
6.02 1023 = 4.81 10-15
collisions/second
