1. LECTURE 9.5 – LE CHATELIER’S PRINCIPLE

2. Today’s Learning Target
LT 8.7 – I can define Le Chatelier’s principle and use this principle to predict how concentration, temperature, and pressure will impact a given equilibrium.

3. What is Le Chatelier’s Principle?

4. I. Le Chatelier’s Principle
“If a system at equilibrium is disturbed by a change in temperature, pressure, or concentration, the system will shift its equilibrium position so as to counteract the effect of the disturbance”
If equilibriums are disturbed, it must respond

5. How do concentration, pressure, and temperature impact equilibrium?

6. I. Le Chatelier’s Principle and Concentration
If we add more of a product/reactant, then our reaction will shift to the other side in order to compensate for this new amount.

7. Class Example I have the following equilibrium: H2O ⇌ H3O+ + OH-
If I add H3O+, then will my reaction shift to the right or to the left?

8. Table Talk I have the following equilibrium: CaCO3 ⇌ CaO + CO2
If I add CaCO3, then will my reaction shift to the right or to the left?

9. II. Le Chatelier’s Principle and Volume/Pressure
If we increase pressure, the reaction shifts to the side with less molecules
If we decrease pressure, the reaction shifts to the side with more molecules

10. Class Example I have the following equilibrium:
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
If I increase the pressure, then will my reaction shift to the right or to the left?

11. Table Talk I have the following equilibrium:
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
If I decrease the pressure, then will my reaction shift to the right or to the left?

12. III. Le Chatelier’s Principle and Temperature
When a reaction is endothermic, heat is listed as a reactant.
Heat + Reactants  Products
When a reaction is exothermic, heat is listed as a product.
Reactants  Products + Heat
Therefore, treat heat like a reactant or a product

13. Class Example I have the following equilibrium:
N2 (g) + 3H2 (g) ⇌ 2NH3 (g) + 92 kJ
If I increase the temperature, then will my reaction shift to the right or to the left?

14. 556 kJ + CaCO3 (s) ⇌ CaO (s) + CO2 (g)
Table Talk
I have the following equilibrium:
556 kJ + CaCO3 (s) ⇌ CaO (s) + CO2 (g)
If I decrease the temperature, then will my reaction shift to the right or to the left?