1. CHEM 1011 Experiment 17: The Law of Chemical Equilibrium and the Le Chatelier Principle

2. Objectives To study chemical equilibria. To investigate the effects of (1) changing concentrations and (2) changing temperature in equilibrium reactions.

3. Introduction Equilibrium: the rate of the forward reaction equals the rate of the reverse reaction.

4. Introduction Le Chatelier Principle: If an external stress is applied to a system in equilibrium, the system reacts in such a way as to partially relieve the stress.

5. Introduction Concentration: Removing or adding reactants can shift equilibrium to the left or right. Common Ion Effect. Spectator ions may influence equilibrium.

6. Introduction Temperature: heat can act as a product or reactant. In endothermic reactions, heat can be considered a reactant and equilibrium will shift to the right. In exothermic reactions, heat can be considered a product and equilibrium will shift to the left.

7. Chemicals and Equipment 0.1 M CuSO 4 1 M NH 3 1 M HCl Saturated NaCl Concentrated HCl 0.1 M KSCN 0.1 M FeCl 3

8. Chemicals and Equipment(cont.) 1 M CoCl 2 H 2 PO 4 - /HPO 4 2- solution Litmus paper