Timeline for Why don't liquids just boil off in the open just as they would in a vacuum?
Current License: CC BY-SA 3.0
14 events
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| Dec 7, 2017 at 23:45 | vote | accept | Ritesh Singh | ||
| Dec 7, 2017 at 22:48 | history | edited | Ritesh Singh | CC BY-SA 3.0 |
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| Dec 7, 2017 at 22:47 | vote | accept | Ritesh Singh | ||
| Dec 7, 2017 at 23:45 | |||||
| Dec 7, 2017 at 21:23 | answer | added | Chemomechanics | timeline score: 4 | |
| Dec 7, 2017 at 18:29 | comment | added | Ritesh Singh | @ChesterMiller Thanks a lot for pointing out that subtle difference between evaporation and boiling! I think I am slow to understand since a part of my question still remains. In a vacuum, I assume that bubbles form in the body of the liquid because some pockets of molecules have the kinetic energy to escape the bonds. But, why shouldn't bubbles form even when there is no vacuum? What stops the pockets of molecules with high kinetic energy from escaping? | |
| Dec 7, 2017 at 18:17 | comment | added | Chet Miller | To answer your questions, No. For the liquid to boil, its equilibrium vapor pressure must be equal to the total pressure of the gases in the system, and not just equal to the partial pressure of the substance in the gas phase. Bubbles can only form below the liquid surface if the pressure within the bubbles is high enough to push back the surrounding atmosphere. | |
| Dec 7, 2017 at 18:10 | history | edited | Ritesh Singh | CC BY-SA 3.0 |
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| Dec 7, 2017 at 18:04 | comment | added | Ritesh Singh | @JonCuster I see, thanks for confirming that! There is something else that makes me wonder. I have edited my question to highlight what intrigued me more. | |
| Dec 7, 2017 at 18:04 | history | edited | Ritesh Singh | CC BY-SA 3.0 |
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| Dec 7, 2017 at 17:59 | comment | added | Ritesh Singh | @ChesterMiller If so, why don't all liquids kept in open just boil all the time (just as they would in vacuum)? Why is the behaviour different in vacuum and in open? Isn't keeping a liquid in open same as keeping it in vacuum since the partial pressure of the liquid in open should approach zero because the vapor would get drifted away quickly? | |
| Dec 7, 2017 at 13:45 | comment | added | Jon Custer | Further to @ChesterMiller 's point, equilibrium vapor pressures of most elements at STP are really really really small, so things can 'evaporate' for billions of years without you noticing. Water is one of the obvious counter-examples, where water vapor is a quite noticeable component of the atmosphere, often not in equilibrium. | |
| Dec 7, 2017 at 13:03 | comment | added | Chet Miller | What you're saying is basically correct. If the partial pressure of the substance in the surrounding air is equal to its equilibrium vapor pressure, it will stop evaporating. If it is less than the equilibrium vapor pressure, it will continue evaporating until its partial pressure reaches the equilibrium vapor pressure. | |
| Dec 7, 2017 at 12:02 | history | edited | Ritesh Singh | CC BY-SA 3.0 |
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| Dec 7, 2017 at 11:56 | history | asked | Ritesh Singh | CC BY-SA 3.0 |