1. Lecture 61/30/06 Seminar TODAY at 4

2. Effect of a catalyst Increases the rate at which reaction gets to equilibrium  Doesn’t change the equilibrium concentrations  How does it affect K? Many industrial processes use heterogeneous catalysts

3. Example For the following reaction: ΔH˚ = 2816 KJ/mol 6 CO 2 (g) + 6 H 2 O (l) ⇄ C 6 H 12 O 6 (s) + 6 O 2 (g) How is the equilibrium yield of C 6 H 12 O 6 affected by: Increasing P CO2 ? Increasing temperature? Removing CO 2 ? Decreasing the total pressure? Removing part of the C 6 H 12 O 6 ? Adding a catalyst?

4. C (s) + CO 2 (g) ⇄ 2 CO (g) P total = 1 atm Endothermic or exothermic? Calculate K p and K c at 850 ˚C T (˚C)CO 2 (mol %)CO (mol %) 8506.2393.77 9501.3298.68 10500.3799.63 12000.0699.94

5. Problem 14-96 A sample of pure SO 3, weighing 0.8312 g was placed in a 1.00-L flask and heated to 1100 K to decompose it partially. 2SO 3 (g) ⇄ 2 SO 2 (g) + O 2 (g) If a total pressure of 1.295 atm was developed, find the value of K c for this reaction at this temperature.

6. Precipitation reactions What are they? Solubility?

7. Solubility Rules Soluble CompoundsExceptions NO 3 - None C 2 H 3 O 2 - (acetate)None Cl -, Br -, I - Compounds with Ag +, Hg 2 2+, Pb 2+ SO 4 2- Compounds with Sr 2+, Ba 2+, Hg 2 2+, Pb 2+ Group 1A and NH 4 + None Insoluble CompoundsExceptions S 2- Group 1A and NH 4 +, Ca 2+, Sr 2+, Ba 2+ CO 3 2-,PO 4 3-, C 2 O 4 2-, CrO 4 2- Group 1A and NH 4 + OH - Group 1A and NH 4 +, Ca 2+, Sr 2+, Ba 2+

8. Equations Pb(NO 3 ) 2 reacts with NaI (aq) to form the insoluble compound, PbI 2. Molecular Equation? Complete Ionic Equation? Net Ionic Equation?

9. Solubility vs. Solubility constant (K sp ) What is the difference? BaSO 4 (s) ⇄ Ba 2+ (aq) + SO 4 2- (aq) Ba 2+ (aq) + SO 4 2- (aq) ⇄ BaSO 4 (s)

10. What is the K sp for AgI if the solubility equals 9.2 x 10 -9 M at 25˚ C?

11. The K sp of AgBr at 100 ˚C is 5 x 10 -10. Calculate the solubility of AgBr at that temperature in molarity.

12. A saturated solution of silver oxalate (Ag 2 C 2 O 4 ) contains 6.9 x 10 -5 M of C 2 O 4 2- at 25˚C. Calculate the K sp of silver oxalate at that temperature.

13. The K sp of MgF 2 = 5.2 x 10 -11. Calculate the solubility in molarity and grams per liter.

14. Comparison of solubility based on K sp AgI (K sp = 8.5 x 10 -17 ) < AgBr (K sp = 5.4 x 10 -13 ) < AgCl (K sp = 1.8 x 10 -10 ) PbI 2 (K sp = 9.8 x 10 -9 ) < PbBr 2 (K sp = 6.6 x 10 -6 ) < PbCl 2 (K sp = 1.7 x 10 -5 ) Can only compare salts with same ion ratio AgCl (K sp = 1.8 x 10 -10 ) vs. Ag 2 CO 3 (K sp = 8.5 x 10 -12 ) Solubility of AgCl = 1.3 x 10 -5 mol/L Solubility of Ag 2 CO 3 = 1.3 x 10 -4 mol/L