1. Chapter 15 Chemical Equilibrium John D. Bookstaver St. Charles Community College Cottleville, MO Chemistry, The Central Science , 11th edition Theodore L. Brown, H. Eugene LeMay, Jr., and Bruce E. Bursten

6. The Equilibrium Constant

23. Heterogeneous Equilibrium

27. Equilibrium Calculations

29. What Do We Know? 1.87 x 10 -3 At equilibrium Change 0 2.000 x 10 -3 1.000 x 10 -3 Initially [HI], M [I 2 ], M [H 2 ], M

30. [HI] Increases by 1.87 x 10 -3 M 1.87 x 10 -3 At equilibrium +1.87 x 10 -3 Change 0 2.000 x 10 -3 1.000 x 10 -3 Initially [HI], M [I 2 ], M [H 2 ], M

31. Stoichiometry tells us [H 2 ] and [I 2 ] decrease by half as much. 1.87 x 10 -3 At equilibrium +1.87 x 10 -3 -9.35 x 10 -4 -9.35 x 10 -4 Change 0 2.000 x 10 -3 1.000 x 10 -3 Initially [HI], M [I 2 ], M [H 2 ], M

32. We can now calculate the equilibrium concentrations of all three compounds… 1.87 x 10 -3 1.065 x 10 -3 6.5 x 10 -5 At equilibrium +1.87 x 10 -3 -9.35 x 10 -4 -9.35 x 10 -4 Change 0 2.000 x 10 -3 1.000 x 10 -3 Initially [HI], M [I 2 ], M [H 2 ], M

33. … and, therefore, the equilibrium constant. K c = [HI] 2 [H 2 ] [I 2 ] = 51 = (1.87 x 10 -3 ) 2 (6.5 x 10 -5 )(1.065 x 10 -3 )

35. If Q = K , the system is at equilibrium.

36. If Q > K , there is too much product, and the equilibrium shifts to the left.

37. If Q < K , there is too much reactant, and the equilibrium shifts to the right.

38. Le Châtelier’s Principle

43. The Effect of Changes in Temperature Co(H 2 O) 6 2+ ( aq ) + 4 Cl ( aq ) CoCl 4 ( aq ) + 6 H 2 O ( l )

44. Catalysts