Explain how vaporization and condesation occur at the molecular level?

Question

Explain how vaporization and condesation occur at the molecular level?

Answer 1

Well the above answer is entirely different from asked question. It has nothing to do with.

As far as i think there is nothing such as condensation or vapourisation in molecular level. It can also be considered as sub nanolevel.

Answer 2

The molecules at the surface of a liquid typically don't have enough energy to break free of the surface. They don't all have precisely the same amount of energy, of course, some of them have a bit more than average, some a bit less.

Every once in a while, one molecule will happen to get bounced against a bit harder by the others. It will break free of the surface of the liquid and become part of the gas on the other side of the boundary. This will have to be a molecule with above average energy, so it will leave the other liquid molecules with less energy on average. (This is why evaporation is a cooling process.)

Condensation occurs when molecules that are part of a gas don't have much energy. Every once in a while, a molecule will have so little energy that it gets stuck to other similar molecules. So long as no molecule in the clump has enough energy to separate from the others, they remain a liquid.

In most realistic scenarios, vaporization and condensation occur in equilibrium. Cooling the gas favors condensation and heating it favors vaporization, shifting the equilibrium.

This is the real reason you can get rain as an air mass climbs a mountain. It has nothing to do with how much water the air mass can hold at a given temperature, since the air isn't "holding" the water. It's just a shift in the equilibrium between the water vapor's condensation and vaporization. The process would occur exactly the same without the air!