Here is a set of examples using LeChatelier's Principle to predict the direction shift of a reaction when it is subjected to a stress.
This video defines the term "stress" and describes what a system does to counteract stresses put upon it.
Source: KhanAcademy
View each of the demonstrations. Respond to the following questions:
Chromate-Dichromate Demo 2H+(aq) + 2CrO42–(aq) <----> Cr2O72–(aq) + H2O(ℓ)
What color is each side of the equilibrium? (be specific, this is important that you observe this)
How can we tell when this system reaches equilibrium?
When H+(aq) was added, the system shifted to the [ right | left ], changing from to
When OH–(aq) was added, the system shifted to the [ right | left ], changing from to
NO2 Tubes Demo 2 NO2(g) <----> N2O4(g) + heat
What color is each side of the equilibrium? (be specific, this is important that you observe this)
When the tubes were heated, the system shifted to the [ right | left ], changing from to
When the tubes were cooled, the system shifted to the [ right | left ], changing from to .
CoCl42– Solutions Demo Co2+(aq) + 4 Cl–(aq) + heat <----> CoCl42–(aq)
What color is each side of the equilibrium? (be specific, this is important that you observe this)
When HCl(aq) was added, the system shifted to the [ right | left ], changing from to .
When Ag+(aq) was added, the system shifted to the [ right | left ], changing from to .
When the tubes were heated, the system shifted to the [ right | left ], changing from to
When the tubes were cooled, the system shifted to the [ right | left ], changing from to .
This is a video of the chromate-dichromate equilibrium reaction with various stresses added.
Sealed tubes of nitrogen dioxide are exposed to various temperatures.
Different stresses are applied to one of the complex ions of cobalt and the system is observed over time..
Print the document below if you did not receive it in class. For each of the steps in the lab, find it in the video and record the results. You may need to rewind several times to be sure you have completed the data table. This lab will be completed in your lab book for class.
Various stresses are applied to the complex ion equilibrium and the results can be seen here.