Timeline for Volume of different gas in a container
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Nov 12, 2014 at 2:17 | comment | added | Jason Patterson | Van der Waals made a model that involved gases that were slightly more real. His model accounted for the volume of the gas particles and the attraction between them. That's all there is to it. Any real gas is a van der Waals system. | |
| Nov 12, 2014 at 2:16 | comment | added | Jason Patterson | I was giving a real world model that compared to this situation, that is, where volume was a constant, not one where Avogadro's law applied. In such a situation pressure and moles are directly proportional rather than volume and moles. In my tire example, all of the scenarios share the same volume. Tires are built to keep a nearly constant volume across a wide range of pressures. Remove half of the nitrogen, same V, smaller n and P. Add it back in using oxygen, same V, original n and P. Double it, same V, greater n and P. All four variables, n,V,P, and T, are interrelated. | |
| Nov 12, 2014 at 1:52 | comment | added | most venerable sir | Sorry, after thinking about it all I still felt there are two important question unanswered: according to your tire analogy, the pressure is not constant because of the later added oxygen, but how do you keep the pressure constant, by putting in nothing? What about releasing half the nitrogen and putting in half the oxygen that you are about to put in? Now, do they still share the same volume? Can you also give a example of a vander wal model? | |
| Nov 3, 2014 at 3:27 | vote | accept | most venerable sir | ||
| Nov 3, 2014 at 2:18 | comment | added | Jason Patterson | @Doeser Avogadro's Law only applies if pressure and temperature are kept constant. That is not the case here, where volume and temperature are constant; that's why they could be canceled in the image from your book. A real life example: I fill a tire with nitrogen until it is at 100kPa pressure. If I then put in an equal number of moles of oxygen, the tire's volume won't increase (much), but the pressure inside the tire will double. The oxygen is filling the same space as the nitrogen. They share a volume, and each has the same partial pressure, 100kPa, and the total gas pressure is 200kPa. | |
| Nov 2, 2014 at 17:07 | comment | added | most venerable sir | But they are proportional according to Avogadro | |
| Oct 31, 2014 at 13:21 | comment | added | Jason Patterson | @Doeser No, that's not what I meant. If I take 2 moles of oxygen and 2 moles of nitrogen and put them in the same container, they will have the same pressure and volume. However, if I have 1 mole of oxygen and 2 moles of nitrogen and I put them in the same container, the gases will have different partial pressures but will have the same volume (the volume of the container.) Mole ratios for gases aren't measured by volume, they're measured by pressure. Check out Dalton's Law of Partial Pressures for more information. | |
| Oct 31, 2014 at 3:13 | comment | added | most venerable sir | Wait even partial pressure of ideal gas depends on their mole ratio which is volume ratio. So you mean they all got the same pressures? | |
| Oct 30, 2014 at 4:24 | history | answered | Jason Patterson | CC BY-SA 3.0 |