Chapt. 6: Chemical Equilibrium

1. Heterogeneous Equilibria

1.1. Phases: gas, solid, liquid

1.2. Heterogeneous Equilibria: between multiple phases

1.3. Equilibrium constant for heterogeneous equilibria

1.4. Activity of pure phases (solids or liquids)

2. Applications of the Equilibrium Constant

2.1. Predictions based on the equilibrium constant

2.2. Extent of reaction

2.3. Reaction quotient (Q)

2.4. Calculating equilibrium pressures and concentrations

3. Solving Equilibrium Problems

4. Le Châtelier's Principle

4.1. Effect of a change in conditions on equilibria

4.2. Effect of a change in concentration

4.3. Effect of a change in pressure

5. Equilibria Involving Real Gases

5.1. Non-ideality

5.2. How to correct Kp for non-ideality

6. Acitivity of pure solid or liquid = 1

7. Q describes the position of a rxn not necessarily at equilibrium

8. ICE tables help organize equilibrium problems

9. Try to make x in the ICE table small. This simplifies the math!

10. You can do "math" with chemical equations

10.1. Adding c.e. means multiplying K

10.2. Multiplying c.e. by n means taking K^n

10.3. Reversing c.e. means taking 1/K

11. "Stress" on an equilibrium shifts reaction in direction that minimizes change

11.1. Add reactant (R) or product (P): rxn shifts to consume it Remove R or P: rxn shifts to replace it

11.2. Decrease the volume: rxn shifts to the side with the smallest n

11.3. Treat energy as R or P to predict effect of T on K

12. Activity coefficients correct for interactions between species

13. The Equilibrium Condition

13.1. How a reaction reaches equilibrium

13.2. Characteristics of chemical equilibrium

13.3. Equilibria are dynamic

14. The Equilibrium Constant

14.1. Law of mass action

14.2. Characteristics of the equilibrium expression

14.3. Equilibria in ammonia synthesis

14.4. Equilibrium position

15. Equilibrium Expressions Involving Pressures

15.1. Ideal gas law

15.2. Equilibrium partial pressures

15.3. Kp vs. K

16. The Concept of Activity

16.1. The reference state

16.2. For a gas, 1 atm

16.3. Definition of activity

17. Equilibria are dynamic but may be so slow that []s appear not to change

18. K is meaningful only at equilibrium

18.1. Can't be = 0 or 1/0

18.2. Large K (>>1) means products favored

18.3. Small K (<<1) means reactants favored

19. Activity is a way to compare the amount of a reactant or product to their standard state and make K unit-less

20. Partial pressures sum to total pressure