1. Applications of the Equil. Constant Predicting the direction of approach to equilibrium: At 448C the equilibrium constant kc for the reaction H 2 (g) + I 2 (g) 2HI(g) is 50.5. Predict in which direction the reaction proceeds to reach equilibrium if we start with 2.0x10 -2 mol of HI, 1.0x10 -2 mol of H 2 and 3.0x10 -2 mol I 2 in a 2.00L container. -compare K to Q

2. Applications of the Equil. Constant Predicting the direction of approach to equilibrium: At 1000K the value of kp for the reaction 2SO 3 (g) 2SO 2 (g) + O 2 (g) is 0.338. Calculate the value for Q p and predict the direction in which the reaction proceeds toward equilibrium if the initial partial pressures are P SO3 = 0.16atm, P SO2 = 0.41atm, P O2 = 2.5atm

3. Calculating k After a mixture of hydrogen and nitrogen gases in a reaction vessel is allowed to attain equilibrium at 427C, it is found to contain 7.38 atm H 2, 2.46atm N 2 and 0.166atm NH 3. From these data, calculate the equilibrium constant k p for the reaction N 2 (g) + 3 H2(g) 2NH 3

4. Calculating k An aqueous solution of acetic acid is found to have the following equilibrium concentrations at 25C: [CH 3 COOH] = 1.65x10 -2 M, [H + ] = 5.44x10 -4 M, [CH 3 COO - ] = 5.44x10 -4 M. Calculate the equilibrium constant k c for the ionization of acetic acid at 25C. CH 3 COOH(aq) H + (aq) + CH 3 COO - (aq)

5. Calculating k Using Initial & Equilibrium Concentrations A closed system initially containing 1.000x10 -3 M H 2 and 2.000x10 -3 M I 2 at 448C is allowed to reach equilibrium and at the equilibrium the HI concentration is 1.87x10 -3 M. Calculate k c at 448C

6. More Calculations with k For the Haber process, k p =1.45x10 -5 at 500C. In an equilibrium mixture of the 3 gases at 500C, the partial pressure of H 2 is 0.928atm and that of N 2 is 0.432atm. What is the partial pressure of NH 3 in this equilibrium mixture? -would you use an ICE chart in this situation? why or why not?

7. More Calculations with k At 500K the reaction PCl 5 (g) PCl 3 (g) + Cl 2 (g) has k p = 0.497. In an equilibrium mixture at 500k, the partial pressure of PCl 5 is 0.860 atm and that of PCl 3 is 0.350atm. What is the partial pressure of Cl 2 in the equilibrium mixture?

8. More Calculations with k A 1.000L flask is filled with 1.000mol of H 2 (g) and 2.000mol of I 2 (g) at 448C. The value of the equilibrium constant K c for the reaction is 50.5. What are the equilibrium concentrations of H 2, I 2, and HI in moles per liter? H 2 (g) + I 2 (g) 2HI(g)

9. More Calculations with k For the equilibrium PCl 5 (g) PCl 3 (g) + Cl 2 (g), the equilibrium constant k p is 0.497 at 500K. A gas cylinder at 500K is charged with PCl 5 (g) at an initial pressure of 1.66atm. What are the equilibrium pressures of PCl 5, PCl 3, and Cl 2 at this temperature?

10. I Hate Quadratic Equations!!!! Do you really have to use it? Maybe not! -if the subtraction of x would cause less than a 5% change in the concentration, then it can be ignored! -Easy way to tell: divide the concentration given in the problem by the given k. If the answer is greater than 100, then x can be ignored

11. ICE without Quadratic Equation Given kc = 2.06x10 -9 at 25C. What is the equilibrium concentration of H+ if the initial concentration of HOBr is 1.25M. HOBr(aq) OBr - (aq) + H + (aq)

12. Another K As if there weren’t enough k’s… k sp = solubility product constant -refers to solids dissolving in aqueous solution Given: Cu(IO 3 ) 2 dissolves in water to form Cu 2+ and 2IO 3-. If k sp = 1.4x10 -7 what is the concentration of Cu 2+ at equilibrium?