1. Le Chatelier's
Principle
Lesson 2

2. Le Chatelier’s Principle
If a system in equilibrium is subjected to a change processes occur that oppose the imposed change and the system shifts to reach a new state of equilibrium. ⇌
Chemists can use this principle to shift the reaction so that there are more Products or Reactants.
products
reactants

3. Le Chatelier’s Principle
If a system in equilibrium is subjected to a change processes occur that oppose the imposed change and the system shifts to reach a new state of equilibrium. ⇌
Chemists can use this principle to shift the reaction so that there are more Products or Reactants.
products
reactants

4. Le Chatelier’s Principle
If a system in equilibrium is subjected to a change processes occur that oppose the imposed change and the system shifts to reach a new state of equilibrium. ⇌
Chemists can use this principle to shift the reaction so that there are more products or Reactants.
reactants
products

5. 1. 1. Increasing the temperature always shifts a reaction in the
1.1 Increasing the temperature always shifts a reaction in the direction that consumes energy.
A B ⇌ C + Energy

6. 1. 2. Increasing the temperature always shifts a reaction in the
1.2 Increasing the temperature always shifts a reaction in the direction that consumes energy.
A B + Energy ⇌ C

7. 1. 3. Decreasing the temperature always shifts a reaction in the
1.3 Decreasing the temperature always shifts a reaction in the direction that produces energy.
A B + Energy ⇌ C

8. 2. 1. Adding a reactant or product shifts the reaction in the opposite
2.1 Adding a reactant or product shifts the reaction in the opposite direction.
A B ⇌ C + Energy
reaction- shift right
stress- increase [A]

9. 2. 2. Adding a reactant or product shifts the reaction in the opposite
2.2 Adding a reactant or product shifts the reaction in the opposite direction.
A B ⇌ C + Energy
left
stress- increase [C]

10. 2. 3. Removing a reactant or product shifts the reaction in the
2.3 Removing a reactant or product shifts the reaction in the opposite direction.
A B ⇌ C + Energy
reaction- shift left
stress- decrease [A]

11. 2. 4. Removing a reactant or product shifts the reaction in the
2.4 Removing a reactant or product shifts the reaction in the opposite direction.
A B ⇌ C + Energy
reaction- shift right
stress- decrease [C]

12. 3. 1. Only changes to (aq) and (g) reactants or products cause the
3.1 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

13. 3. 1. Only changes to (aq) and (g) reactants or products cause the
3.1 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

14. 3. 1. Only changes to (aq) and (g) reactants or products cause the
3.1 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)
no shift!

15. 3. 2. Only changes to (aq) and (g) reactants or products cause the
3.2 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

16. 3. 2. Only changes to (aq) and (g) reactants or products cause the
3.2 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)
shifts to products

17. 3. 3. Only changes to (aq) and (g) reactants or products cause the
3.3 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

18. 3. 3. Only changes to (aq) and (g) reactants or products cause the
3.3 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)
shifts to products

19. 3. 4. Only changes to (aq) and (g) reactants or products cause the
3.4 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

20. 3. 4. Only changes to (aq) and (g) reactants or products cause the
3.4 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)
shifts to reactants

21. 3. 5. Only changes to (aq) and (g) reactants or products cause the
3.5 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

22. 3. 5. Only changes to (aq) and (g) reactants or products cause the
3.5 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)
shifts to products

23. 3. 6. Only changes to (aq) and (g) reactants or products cause the
3.6 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)

24. 3. 6. Only changes to (aq) and (g) reactants or products cause the
3.6 Only changes to (aq) and (g) reactants or products cause the equilibrium to shift
(s) and (l) do not!
You can change the concentrations of (aq) and (g)
(s) and (l) have constant concentrations
CaCO3(s) + 2H+(aq) + 2Cl-(aq) ⇌ Ca2+(aq) + 2Cl-(aq) + CO2(g) + H2O(l)
no shift- liquids have constant concentration-drop in the bucket syndrome!

25. 4.1 Adding a catalyst does not shift the equilibrium, however it does allow you to reach equilibrium faster and both the forward and reverse rates are increased by the same amount.

26. 4.1 Adding a catalyst does not shift the equilibrium, however it does allow you to reach equilibrium faster and both the forward and reverse rates are increased by the same amount.
products
reactants

27. 4.1 Adding a catalyst does not shift the equilibrium, however it does allow you to reach equilibrium faster and both the forward and reverse rates are increased by the same amount.
products
reactants
products
reactants

28. 5.1 Adding an inert (non-reactive) gas does not shift the equilibrium.
2NH3(g) ⇌ N2(g) H2(g)

29. 5.1 Adding an inert (non-reactive) gas does not shift the equilibrium.
2NH3(g) ⇌ N2(g) H2(g)
Adding Ne(g)

30. 5.1 Adding an inert (non-reactive) gas does not shift the equilibrium.
2NH3(g) ⇌ N2(g) H2(g)
Adding Ne(g)
No shift!