The saturated vapor pressure is designated as the gas pressure in a closed container when the evaporation process has reached an equilibrium (when there are as many molecules returning to the liquid as there are escaping it). Doesn't that mean that vapor pressure is dependant on the volume? Why not?

And how exactly is vapor pressure connected to the boiling point? I know that a liquid boils when its vapor pressure becomes equal to the external pressure but why is that? Is it because the pressure in the bubbles, that are formed by heating the liquid, is the same vapor pressure?

Thanks in advance.

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    $\begingroup$ Related: chemistry.stackexchange.com/questions/38653/… $\endgroup$ Jun 6, 2016 at 15:55
  • $\begingroup$ So I was right? The pressure inside a bubble, which was formed by heating, is the vapor pressure? And what about my first question? $\endgroup$ Jun 6, 2016 at 16:07
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    $\begingroup$ Yes, that's right. As for your first question: no, it doesn't. Gas with some liquid in it behaves quite differently from gas alone. You double the volume, but the pressure would not drop by a factor of 2. It would not change at all, for some liquid would evaporate and maintain the same pressure that was before. $\endgroup$ Jun 6, 2016 at 18:24


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