#### Learning Objectives and Key Terms

Key Terms and ideas you should know

- Law of mass action
- Dynamic equilibrium
- Homogenous equilibrium with examples
- Write equilibrium constant expressions for the equations provided
- Heterogeneous equilibrium and examples
- Write equilibrium constant expressions for heterogeneous equilibria
- Difference between concentration quotient and equilibrium constant Q
_{c}Vs K_{c} - Factors affecting chemical equilibrium: need to elaborate each
- Concentration
- Change in Pressure / Volume for gaseous reactants
- Temperature
- Addition of a catalyst
- Addition of an inert gas

- Le Chatliers principle definition
- Predicting shift in equilibrium based on the variation of concentration, temperature, pressure / volume change all possible combinations. One example for each type of shift like
- Adding a reactant
- Adding a product
- Removing a reactant
- Removing a product
- Adding heat to an exothermic / endothermic reaction
- Taking away heat from an exothermic / endothermic reaction
- Adding an inert gas without change in volume / with change in volume

- Values of Kc and its implication
- What does it mean if the value of Keq is very large / very small / = 1
- What will the value of Kc be if the reaction is reversed
- What happens to the value of Kc if the equation is multiplied by a coefficient
- Relation between Kc and Kp

- Problems
- Determining molar concentrations of reactants and products
- Generate an ICE table to calculate equilibrium concentrations
- Determine value of Kc form equilibrium concentrations
- Find the equilibrium concentration if the equilibrium constant is given
- Find the equilibrium concentration of one of the reactants in a reaction when the equilibrium expression is a perfect square.
- Find the equilibrium concentration when the equilibrium constant is given and the equilibrium expression is
**NOT**a perfect square; you will use the quadratic equation. - Determine the new equilibrium concentrations of reactants when a stress is applied by adding a known quantity of reactant. Problems on Le Chatliers Principle.
- Predicting the quantity of a reactant needed to obtain a known increase in the concentration of one of the products. Le Chatliers principle.
- Predicting concentrations of reactants or products when Kc is known and the value of Kc is small – using the 100
^{th}rule. - Problems converting Kc to Kp and Vice Versa

#### Spontaneity of Chemical Reactions

- Define spontaneity
- Define Entropy
- Predicting entropy of chemical reactions using states of matter, number of entities and temperature changes.

- Significance of free energy
- Predicting spontaneity based on values of free energy
- When free energy or G = O
- When free energy or G = < O or negative
- When free energy or G = > O or positive

- Relationship between G and equilibrium constant G = -RTlnKc or G = -RTln Kp, ln can be changed to log but multiply by 2.303 appropriately
- Gibbs-Helmholtz equationG = H -TS
- Predicting spontaneity based on values provided
- Why can’t Kc have a negative value?
- What is the effect of the presence of a catalyst on equilibrium constant?
- Predict the temperature at which a reaction would become spontaneous. Using Gibbs-Helmholtz equation, assumption is that the system is at equilibrium, then calculate the temperature ‘T’

**Web Links**

##### Chemical Equilibrium

1. Wikipedia

2. ThinkQuest

3. Shodor

##### Law of Mass Action

1. Wikipedia

##### Reaction Quotient

2. Chem1

##### Equilibrium Constants

1. Chemguide

2. Wikipedia

##### Haber Process

1. Aus-e-tute

3. Chemguide