1. Le Chatelier’s Principle Review

2. Evaluation/Assessment:
Objective:
Today I will be able to:
Apply Le Chatelier’s Principle to explaining how equilibrium systems adjust to stresses of concentration, temperature, pressure and volume
Evaluation/Assessment:
Informal assessment: Monitoring student interactions and questions as they complete the Le Chatelier’s Principle practice.
Formal assessment: Analyzing student responses to practice and the exit ticket
Common Core Connection
Build Strong Content Knowledge
Reason abstractly and quantitatively
Make sense of problems and persevere in solving them

3. Lesson Sequence Evaluate: Warm – Up
Explain: Le Chatelier’s Principle Notes
Elaborate: Le Chatelier’s Principle Practice
Evaluate: Exit Ticket

4. Warm - Up
Write the equilibrium constant expression for the following reactions
a. O3 (g) + NO(g) → O2(g) + NO2(g)
b. 2CO(g) + O2(g) → 2CO2(g)
c. NH4NO3(s) → N2O(g) + 2H2O(l)
d. 2H2O(g) → 2H2(g) + O2(g)

5. Objective Today I will be able to:
Apply Le Chatelier’s Principle to explaining how equilibrium systems adjust to stresses of concentration, temperature, pressure and volume

6. Homework Finish Le Chatelier’s Principle Practice
Wear closed toe shoes for lab Wednesday and Thursday
Study for Equilibrium Constant/ Le Chatelier’s Quiz Friday

7. Agenda Warm – Up Le Chatelier’s Principle Notes
Le Chatelier’s Principle Practice
Exit Ticket

8. Le Chatelier’s Principle Review
Answer the following questions with a partner

9. Determine whether the following statements are true or false
At equilibrium:
The rate of the forward reaction equals the rate of the reverse reaction
The concentration of reactants and products is always equal
The concentrations of reactants and products remain constant

10. Answers
True
False

11. True or False
Le Chatelier’s principle describes how a system at equilibrium restores equilibrium after it has been “stressed”

12. Answer
True

13. What different “stresses” can be applied to a system?
Adding/ Removing Reactants
Adding/ Removing Products
Changing Pressure
Changing Volume
Changing Temperature

14. 2 A (g) + B (g)  C (g) + X kJ
For the reaction above complete the table below
Stress
Direction of Shift
[A]
[B]
[C]
Add B
____
Add C
___
Remove A
Remove C
Increase Pressure
Increase Volume
Decrease Temp

15. 2 A (g) + B (g)  C (g) + X kJ
For the reaction above complete the table below
Stress
Direction of Shift
[A]
[B]
[C]
Add B
right
decrease
____
increase
Add C
Left
Increase
___
Remove A
Decrease
Remove C
Right
Increase Pressure
Increase Volume
Decrease Temp

16. 2NH3(g) kJ↔ N2(g) + 3H2(g)
For the reaction above complete the table below
Stress
Direction of Shift
[NH3]
[N2]
[H2]
Keq
Add [N2]
____
Add NH3
___
Remove NH3
Remove hydrogen
Increase Pressure
Increase Volume
Decrease Temp

17. Le Chatelier’s Principle Notes

18. Le Chatelier’s Principle
When an equilibrium system is subjected to a change, the system will “shift” to counteract the change
Example reaction
A (g) + B (g)  C (g) + X kJ

19. A (g) + B (g)  C (g) + X kJ
Add a reactant – moves to product side to consume it
Add a product – moves to reactant side to consume it
Remove a reactant – moves to reactant side to produce more
Remove a product – moves to product side to produce more

20. A (g) + B (g)  C (g) + X kJ
Increase temperature – because it is an exothermic reaction, shift to the reactants side
Decrease temperature – shift to the products
The opposite would be true for an endothermic reaction

21. A (g) + B (g)  C (g) + X kJ
Increase pressure – move to side with less moles of gas
Decrease pressure – move to side with more moles of gas
Increase volume – move to side with more moles of gas
Decrease volume – move to side with less moles of gas

22. Le Chatelier’s Principle Practice

23. Exit Ticket Given the following reaction:
Use Le Chatelier’s principle to determine what would happen if the following changes were made
Increase the concentration of N2
Increase the concentration of NH3
Remove NH3 from the reaction after it is made