VaporPressure

VaporPressure - Why does vapor pressure not depend on...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Why does vapor pressure not depend on atmospheric pressure? Many people were confused about vapor pressure vs atmospheric pressure on the last quiz. Here’s the best way I can explain it. Suppose you have a beaker half-full of water, with a cover on top. There is an equilibrium between the liquid water and the water vapor: H 2 O (l) ↔ H 2 O (g) P vap is a measure of the concentration of water vapor in the space above the liquid water. As you heat up the beaker, more water molecules can break the intermolecular H-bonds and go into the gas phase, so P vap increases. In fact, because there is a lid on top (let’s assume it’s glued on very tightly), you can even get the water hotter than 100 0 , which builds up more than 1atm of pressure in the beaker. If you heat it enough, you will eventually get so much pressure built up that the beaker explodes. Now, imagine that the beaker is open on top:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Instead of a lid, there is 1atm of atmospheric pressure pushing down on the H 2 O (g) This actually acts much like a lid, except that some water vapor can leak out slowly (which is
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

VaporPressure - Why does vapor pressure not depend on...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online