1. Time for… fun with probes!

2. Chapter 15: Chemical Equilibria

7. What is the equilibrium expression for Fe 2 S 3 (s) 2 Fe 3+ (aq) + 3 S 2- (aq) 1.1: 2.2: 3.3: 4.4:

8. Manipulating Equilibrium Expressions : N 2 (g) + 3 H 2 (g)  2 NH 3 (g) K = =5.5 x 10 5 Reversing Reactions Multiplying by a Factor

9. Manipulating Equilibrium Expressions : Adding Reactions Cu(OH) 2 (s)  Cu 2+ (aq) + 2 OH - (aq) K 1 = 1.6x 10 -19 Cu 2+ (aq) + 4 NH 3 (aq)  Cu(NH 3 ) 4 2+ (aq)K 2 = 1.2 x 10 12 Cu(OH) 2 (s) + 4 NH 3 (aq)  Cu(NH 3 ) 4 2+ (aq) + 2 OH - (aq)K = ?

12. Cu(NH 3 ) 4 2+ (aq)  Cu 2+ (aq) + 4 NH 3 (aq) K = 8.5 x 10 -13 If [Cu 2+ ] = 1.0 x 10 -6, [NH 3 ] = 1.0 x 10 -3, [Cu(NH 3 ) 4 2+ ], then … 1.It is at equilibrium 2.Reaction goes forwards 3.Reaction goes backwards

13. Equilibrium Calculations: Your Pathway to Happiness 1.Write the equilibrium expression 2.Determine Q 1.if Q = K, it’s at equilibrium 2.if Q < K, reactants go to form products 3.if Q > K, products go to form reactants 3.Call the amount reacting “x” 4.Solve for x in the equilibrium expression 5.Use x to determine equilibrium concentrations

14. Given these initial concentrations, what will the final concentrations be when equilibrium is reached?

15. K in terms of pressure: K p vs. K c K p = K c (RT)  n  n = change in numbers of moles of gas 2 NH 3 (g) N 2 (g) + 3 H 2 (g) K c = 5.8 x 10 5 K p =

20. LeChatelier’s Principle: Doing the math 1-Liter flask contains 0.50 mol butane and 1.25 mol isobutane (at equilibrium). 0.50 mol butane are added. What happens, and what is the result?