1. Le Chatelier’s Principle & Catalysts

2. In a system at equilibrium, adding a catalyst will increase the rates of both the forward and reverse reactions equally. Thus, adding a catalyst will have no net effect on the final equilibrium of the system. Reaction Coordinate Potential Energy→

3. Le Chatelier’s Principle & Catalysts Ex.1) When a catalyst is added to a system at equilibrium, the concentrations of the products will (1) increase (2) decrease (3) remain the same If adding a catalyst speed up both the forward and reverse reactions equally, then neither reaction is favored over the other. Thus all of the components of the system will remain the same!

4. Le Chatelier’s Principle & Catalysts Ex.2) When a catalyst is used on an equilibrium system, the forward reaction will proceed (1) faster and the products will be favored (2) faster but neither the products nor the reactants will be favored (3) slower and the reactants will be favored (4) slower but neither the products nor the reactants will be favored

5. Le Chatelier’s Principle & Catalysts Ex.3) Which of the following statements regarding a system at dynamic equilibrium is NEVER true? (1) the rate of the forward reaction is equal to the rate of the reverse reaction (2) the concentrations of the reactants are less than the concentrations of the products (3) the concentrations of the reactants are greater than the concentrations of the products (4) the forward reaction and the reverse reaction have both stopped

6. Le Chatelier’s Principle & Catalysts Ex.4) When a catalyst is added to an equilibrium system, the activation energy will be (1) decreased and equilibrium will shift to the right (2) decreased and equilibrium will shift to the left (3) decreased and equilibrium will remain the same (4) increased and equilibrium will remain the same Ex.5) If some KCl is added to a saturated aqueous solution of KClO 3, then the concentration of aqueous chlorate ions (ClO 3 1- ) will (1) increase (2) decrease (3) remain the same

7. Le Chatelier’s Principle & Catalysts Ex.6) Consider the reaction at STP and at equilibrium. H 2(g) + Cl 2(g)  2 HCl (g) Which change will result in an increase in the concentration of Cl 2(g) ? (1) decreasing the pressure on the system (2) decreasing the concentration of Cl 2(g) (3) increasing the concentration of H 2(g) (4) increasing the concentration of HCl (g)

8. Le Chatelier’s Principle & Catalysts Ex.7) Based on the equilibrium system, 4 NH 3(g) + 5 O 2(g)  4 NO (g) + 6 H 2 O (g) + 768.28 kJ Which of the following changes will produce the greatest yield of nitrogen monoxide? (1) an increase in pressure and an increase in temp. (2) an increase in pressure and an decrease in temp. (3) an decrease in pressure and an increase in temp. (4) an decrease in pressure and an decrease in temp.

9. Le Chatelier’s Principle & Catalysts Ex.8) The addition of a catalyst to a system at equilibrium will increase the rate of (1) the forward reaction only (2) the reverse reaction only (3) both the forward and reverse reactions equally (4) neither the forward nor reverse reactions