1. 16-2: The Law of Chemical Equilibrium

2. Remember… Chemical equilibrium is achieved when the rate of the forward rxn is equal to the rate of the reverse reaction

3. The Equilibrium Constant aA + bB  cC + dD K eq = [C] c [D] d [A] a [B] b

4. Example 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2

5. Chemical Equilibrium Every rxn has specific K eq at a given temperature. Remember that we are considering the conc. at equilibrium of each substance raised to the power of its coefficient. Conc. are in molarity

6. Law of Chemical Equilibrium Law of Chemical Equilibrium: every reversible rxn proceeds to an equilibrium state that has a specific ratio of the conc of reactants to products expressed by K eq If K eq is very large (much greater than one), then the rxn lies to the right If K eq is very small (much less than one), then the reaction lies to the left.

7. Law of Chemical Equilibrium Homogeneous equilibrium: all reactants and products are in the same state Heterogeneous equilibrium: reactants and products are in more than one state

8. Law of Chemical Equilibrium In the K eq expression, solids and liquids do NOT actually appear. Why? Their concentrations do not substantially change and are figured into the equilibrium constant Reaction quotient (Q): used to determine if a reaction is at equilibrium If K>Q, then the reaction will proceed to the right If K<Q, then the reaction will proceed to the left If K=Q, then the reaction is at equilibrium