1. Learning Goals identify common equilibrium constants, including Keq, Ksp, Kw, Ka, Kb and write the expressions for each solve problems related to equilibrium by performing calculations involving concentrations of reactants and products

2. Equilibrium Law mathematical description of chemical system at equilibrium defined by the equilibrium constant, K Complete Inv. 7.2.1 on p. 473-474

3. Writing Equilibrium Law Equations For aA + bB cC + dD, K = [C] c [D] d (omit units) [A] a [B] b omit (s) and (l) include only (aq) and (g) Ex. H 2(g) + S (l) H 2 S (g) Ex. NH 3(g) + H 2 O (l) NH 4 + (aq) + OH - (aq) p. 431 #1-3, p. 434 #1

4. Calculating K Write the equilibrium law equation. Substitute [ ] eq K can be used to predict the equilibrium position (Review Equilibrium Position table in lesson 1 and add a column for K.)

5. Sample Problem 2 (p. 430) In a closed vessel at 500°C, N 2(g) + 3 H 2(g) 2 NH 3(g) The equil. conc. of N 2, H 2 and NH 3, respectively, are 1.50 x 10 -5 M, 3.45 x 10 -1 M and 2.00 x 10 -4 M. Calculate K.

6. Sample Problem 3 (p. 431) In a closed vessel at 500°C, 2 NH 3(g) N 2(g) + 3 H 2(g) The equil. conc. of N 2, H 2 and NH 3, respectively, are 1.50 x 10 -5 M, 3.45 x 10 -1 M and 2.00 x 10 -4 M. Calculate K. K (synthesis of ammonia) K’ (decomposition of ammonia) Mathematical relationship b/w K and K’? K = 1/K’

7. What does the magnitude of K tell us about the equilibrium position? A. In a closed system at 25°C, 2 CO (g) + O 2(g) 2 CO 2(g) K = 3.3 x 10 91 B. Decomposition of water at 1000°C, 2 H 2 O (g) 2 H 2(g) + O 2(g) K = 7.3 x 10 -10 C. NO 2(g) + NO (g) N 2 O (g) + O 2(g) K = 0.951

8. Homework p. 436 #1-6