The speed of a gas particle is 1600 km/h. Why don't the molecules from a perfume bottle in NY reach LA?

Distance from NY to LA about 5000 km, so technically they should reach LA in about 3 hours.


I know this has something to do with diffusion, but a little more in depth answer please!The speed of a gas particle is 1600 km/h. Why don't the molecules from a perfume bottle in NY reach LA?
Gas molecules can only travel a very small distance before they collide with each other. This is known as the mean free path. In fact the calculations show us that the average gas molecule with collide approximately every 0.1 nanoseconds!





Eventually, if nothing else interfered with the perfume gas molecules they would travel 5000km, but this would take a very long time. And don't forget that even when they travelled 5000km they would have travelled in every possible direction, and would not be concentrated enough in the one spot for our noses to detect.The speed of a gas particle is 1600 km/h. Why don't the molecules from a perfume bottle in NY reach LA?
The mean free path is the average distance a gas molecule will travel before it collides with another particle. After collision the particle will change its direction randomly. Thus, instead of moving in a straight line for a large distance, a particle moves in a zig-zag path tends to stay in the initial region.