Can evaporation occur without heat?

Question

Also, does salt freeze ice or melt ice?? This question has seriously been KILLING me.

so yeah. (: thankyou.

Answer 1

yes they it does melt and salt does melt snow

Answer 2

Evaporation is the change of thermal energy of a liquid into latent heat of the vapor. You cannot have evaporation without thermal energy (actually, nothing exists without thermal energy). I say that because most people mean "thermal energy" when they say the word "heat". Heat is the transfer of thermal energy from one temperature to another. So heat is something that happens, not something that an object can "have."

That energy is stored in a liquid is in the form of molecules bouncing around. Some of the more energetic molecules get enough energy to bounce out of the forces holding the liquid together. That's evaporation. In evaporation, there is a transfer of energy from the liquid to the vapor, but not necessarily across a temperature gradient, so it's not normally called heat. Instead, it's called latent heat of evaporation, but it is very similar to "normal heat", so you can probably think of it as heat. As the energy is transferred from liquid to vapor, the liquid starts to cool off. To keep the evaporation going, heat must be added to the system--so in that sense evaporation definitely requires heat. You either add heat by putting a pot on the stove, or heat gets passively transferred to the liquid from the surrounding air, since the evaporating liquid is cooler than the surroundings. You can't avoid that transfer of heat, so yes, evaporation requires heat to proceed. If there was no heat transfer, evaporation would continue to cool the liquid down colder and colder until it freezes, and then it will continue to sublime until it is totally evaporated or it approaches absolute zero. But there will always be something warmer than it nearby that transferrers heat to it to keep it warm. You can actually put water under a vacuum pump and it will boil until it gets so cold that it freezes.

Salt lowers the melting temperature of ice, so it melts it and it brings down the temperature at the same time.