UTF-8Avogadro's law: The V-n relationship at constant temperature and pressureGas Laws: Avogadro's Law
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For our final gas law, we'll explore the relationship that exists between the number of particles and volume of a gas (at constant temperature and pressure).
We'll do this experiment a little differently than the ones we did for the other three gas laws. This time we'll ask you to run a series of trials, one right after another, each time changing the number of molecules of gas and observing how the volume is effected. Some details about our simulator:
The simulator currently contains 120 molecules. The piston is not in a fixed position; it can expand or contract so as to maintain a constant pressure.
The small triangle on the right side of the bar graph (it will appear immediately after starting the simulator) records the average volume over the last 20,000 fs.
Since we are using a two-dimensional model, what we are calling "volume" on the bar graph below is really the length the piston moves from the wall (in angstroms).
Instructions:
1. Click Run. Observe any changes in the volume of the container. Click Stop when the small triangle on the bar graph stays relatively constant (in other words, for this and each other trial on this page, let the simulator run for about 60,000 fs).
2. Record the average volume of the container (the level of the triangle, not the bar) by writing it in the "120 molecules" box below.
volume (length in angstroms)
3. Select the "100 molecules" button.
4. Click Run and again observe any changes in volume. Stop the simulation when the volume stays relatively constant (remember, wait at least 60,000 fs).
5. Record the volume of the 100 molecules container by writing the value in the appropriate box.
6. Repeat Steps 3-5 for the remaining four buttons.
a) b)
c) d)
The direct relationship between moles and volume of a gas is known as Avogadro's law. This has many practical applications. Later on, we'll see how pumping air in your car or bike tire is an example of Avogadro's Law.
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130.030.015true130.030.0130.030.011page5.cml1111index.cml1111page7.cml1111130.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.030.0true30.030.030.030.030.030.030.030.0org.concord.mw2d.activity.AtomContainerpage6$0.mmlfalsefalseorg.concord.modeler.PageBarGraphX: Obstacle #0volume (length in angstroms)0.102100250true840true-66330100.040.023.23717838581171730.030.030.030.0org.concord.modeler.PageButtonRunorg.concord.mw2d.models.MolecularModel0Execute MW scriptorg.concord.modeler.PageButtonStoporg.concord.mw2d.models.MolecularModel0Execute MW script30.030.030.030.0org.concord.modeler.PageRadioButton120 moleculesPuts 120 molecules total in the containertruetrueorg.concord.mw2d.models.MolecularModel01138816545877Execute MW scriptorg.concord.modeler.PageRadioButton100 moleculesPuts 100 molecules total in the containertrueorg.concord.mw2d.models.MolecularModel01138816545877Execute MW scriptorg.concord.modeler.PageRadioButton80 moleculesPuts 80 molecules total in the containertrueorg.concord.mw2d.models.MolecularModel01138816545877Execute MW scriptorg.concord.modeler.PageRadioButton60 moleculesPuts 60 molecules total in the containertrueorg.concord.mw2d.models.MolecularModel01138816545877Execute MW scriptorg.concord.modeler.PageRadioButton40 moleculesPuts 40 molecules total in the containertrueorg.concord.mw2d.models.MolecularModel01138816545877Execute MW scriptorg.concord.modeler.PageRadioButton20 moleculesPuts 20 molecules total in the containertrueorg.concord.mw2d.models.MolecularModel01138816545877Execute MW script30.030.030.030.030.030.0true30.030.030.030.01130.030.014trueorg.concord.modeler.PageTextField10<html>
120 molecules
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100 molecules
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80 molecules
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60 molecules
</html>org.concord.modeler.PageTextField10<html>
40 molecules
</html>org.concord.modeler.PageTextField10<html>
20 molecules
</html>30.030.030.030.030.030.030.030.030.030.030.030.030.030.0org.concord.modeler.PageMultipleChoicetrue4625170<html>
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<font size="3" face="Verdana">Which of the four graphs below best
represents the relationship between the number of particles and volume of
a gas (at constant pressure and temperature)?</font>
</body>
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trueabcd3 falseLine30.030.030.030.0truetrue30.030.0graph1.gifgraph2.gif30.030.0truetrue30.030.030.030.0graph3.gifgraph4.gif30.030.030.030.0org.concord.modeler.PageMultipleChoicetrue3300140<html>
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<font size="3" face="verdana">As the moles decreased, what happened to the
volume?</font>
</body>
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truevolume increasedvolume decreasedvolume remained the same1 falseLineorg.concord.modeler.PageMultipleChoicetrue2400140<html>
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<font size="3" face="verdana">Which of the following best explains what
occurred as the number of particles decreased?</font>
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truethe strength and/or rate of collisions increasedthe strength and/or rate of collisions decreased1 falseLine30.030.0true30.030.0org.concord.modeler.PageMultipleChoicetrue3450150<html>
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<font size="3" face="verdana">Had we run the series of trials by
increasing the number of moles each time, rather than decreasing, what
would have happened to the volume from one trial to the next?</font>
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truevolume would have increasedvolume would have decreasedvolume would have remained the same0 falseLine30.030.030.030.0true30.030.011130.030.011page5.cml1111index.cml1111page7.cml111111