UTF-8LeChatelier's Principle
by Ed O'Sullivan, Brookfield Academy
I. Concentration Changes
The simulator below contains molecules of A2 (green) and B2 (blue). When run, the following reversible reaction will occur:
A2 + B2 2AB
Instructions:
1) Run the model until equilibrium is reached (all concentrations constant) and then stop the simulator. Base your decision on when the average number of molecules of each substance (indicated by the small triangle which will appear on the right side of each bar graph) stays relatively constant. Should take about 1-1.5 minutes.
2) Record the average number of molecules of A2, B2, and AB at equilibrium.
3) Add 7-8 more A2 molecules (the smaller molecules in green) by using the Duplicate the selected object tool (click on tool, then click on an A2 molecule, then drag a new molecule). If a Reset recorder warning appears, just click Yes or Yes, but don't show again.
4) Run model from where you left off until equilibrium is reestablished. Stop the model and record the new equilibrium values.
5) Remove 7-8 A2 molecules by clicking on one of the atoms in an A2 molecule and hitting the delete key (make sure to click on an atom and not the bond between the atoms).
6) Repeat step 4.
7. Run the simulator again to see if your predictions were correct, first removing AB, then adding AB. Each time wait for equilibrium to be reestablished and then record the average number of molecules of each.
After removing AB: After adding AB:
< next >
130.030.016true130.030.0true130.030.016true130.030.030.030.030.030.014true30.030.030.030.0truetrue30.030.030.030.0truetruedouble.gif30.030.030.030.0org.concord.mw2d.activity.ChemContainerLeChat-conc$0.mmlfalseorg.concord.modeler.PageBarGraph4Number of A2Number of A2 molecules100280true1020true0.020.015.0org.concord.modeler.PageBarGraph4Number of B2Number of B2 molecules100280true1020true0.020.015.0org.concord.modeler.PageBarGraph4Number of ABNumber of AB molecules100280true1020true0.020.00.030.030.030.030.0true30.030.030.030.030.030.030.030.0truetrue30.030.0org.concord.modeler.PageTextField6080<html>
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Number of A2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of B2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of AB
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false30.030.030.030.0truetruetruetruetrue30.030.030.030.030.030.0org.concord.modeler.PageTextField6080<html>
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Number of A2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of B2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of AB
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false30.030.030.030.0org.concord.modeler.PageMultipleChoicefalse4520150<html>
<head>
</head>
<body>
<font face="verdana" size="3">After adding additional A<sub>2</sub>, which
of the following occurred (click all that apply)?</font>
</body>
</html>
true<html>B<sub>2</sub> increased<html><html>B<sub>2</sub> decreased</html>AB increasedAB decreased1 2falseLine30.030.030.030.0truetrue30.030.030.030.0org.concord.modeler.PageTextField6080<html>
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Number of A2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of B2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of AB
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false30.030.030.030.0org.concord.modeler.PageMultipleChoicefalse4580150<html>
<head>
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<body>
<font face="verdana" size="3">After removing A<sub>2</sub>, which of the
following occurred (compare to step 4; click all that apply)?</font>
</body>
</html>
true<html>B<sub>2</sub> increased<html><html>B<sub>2</sub> decreased</html>AB increasedAB decreased0 3falseLine30.030.030.030.0org.concord.modeler.PageMultipleChoicefalse4360140<html>
<head>
</head>
<body>
<font face="verdana" size="3">Predict the effect of removing AB (click all
that apply)?</font>
</body>
</html>
<html>B<sub>2</sub> will increase<html><html>B<sub>2</sub> will decrease</html><html>A<sub>2</sub> will increase<html><html>A<sub>2</sub> will decrease</html>1 3falseLineorg.concord.modeler.PageMultipleChoicefalse4360140<html>
<head>
</head>
<body>
<font face="verdana" size="3">Predict the effect of adding AB (click all
that apply)?</font>
</body>
</html>
<html>B<sub>2</sub> will increase<html><html>B<sub>2</sub> will decrease</html><html>A<sub>2</sub> will increase<html><html>A<sub>2</sub> will decrease</html>0 2falseLine30.030.030.030.030.030.030.030.0org.concord.modeler.PageTextField6080<html>
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Number of A2
</body>
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falseorg.concord.modeler.PageTextField6080<html>
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Number of B2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of AB
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falseorg.concord.modeler.PageTextField6080<html>
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Number of A2
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falseorg.concord.modeler.PageTextField6080<html>
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Number of B2
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Number of AB
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false30.030.0130.030.0LeChat-temp.cml30.030.030.030.0