Do All Liquids Evaporate?

If you spill gasoline, eventually the spill will evaporate leaving residue from the additives behind. But, what about cooking oils? …Do they eventually evaporate? I would assume so, but who waits long enough to find out? :slight_smile:

The vapor pressure of a liquid indicates the evaporation rate. (Vapor pressures are often available in references, evaporation rates, as such are not.)

There are many, many liquids that evaporate so slowly that you might just as well decide that they don’t at all. For example, Polyethylene glycol. It is huge chains that can vary in length. You can buy various grades, being different average molecular weights. PEG 300, for example, averages around a molecular weight of 300. It evaporates very slowly. But, PEG 600 is much slower. Get much higher and you’ll have to warm it to get it to be a liquid. They sell grades into the multiple thousands. I have personally worked with PEG 6000. But, hey, it might be available even higher than that.

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