As I understand it, evaporation is thought of as a phase transition from a liquid into a gas. Individual molecules get enough energy to break surface tension, and flung up into the gas. A gas that's saturated with water vapor can precipitate out when the temperature goes below the saturation point. e.g. dew.
Is it useful to think of this as the liquid dissolving in the gas, much like a solid dissolves into a liquid rather than thinking of it as two gasses mixed together? i.e. are these fundamentally related concepts, but just occurring in different states of matter? They seem rather similar in their behavior. Water at room temperature and under atmospheric pressure easily "dissolves" in air, but iron doesn't.
If not, why is it not thought of in this way?
Best Answer
I don't think that's a useful perspective to adopt. Fundamentally, dissolution (or solvation) involves particle of the solute being pulled away from the bulk and surrounded by particles of the solvent. Whether this occurs or not depends on how strong the solute-solvent intermolecular forces are relative to the solute-solute forces which bind the solute together. For a given solute under fixed conditions, different solvents will dissolve it more or less readily.
On the other hand, vaporization involves the atoms/molecules of the liquid gaining a sufficient amount of energy to leave the liquid phase. When this happens, the molecules become essentially free, and in particular they are not surrounded by a solvation shell like dissolved solute particles are. This process is not influenced very much by the nature of the gas which exists above the surface of the liquid, and would proceed even if there were no gas above the liquid at all.
Ultimately, solvation is a process which involves the attractive intermolecular forces from a solvent while vaporization does not. Put differently, vaporization is a process which occurs to a single substance while solvation is a physical reaction between two different substances. I think that's too important a distinction to sweep under the rug.