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Class average for Exam I 70

Class average for Exam I 70. Fe 3+ (aq) + 3 OH - (aq). Fe(OH) 3. [Fe 3+ ][OH - ] 3 = 1.1 x 10 -36. [y][3y] 3 = 1.1 x 10 -36. If there is another source of OH - (NaOH) that provides a higher [OH - ] then that is the value of [OH - ] to be used. pH and solubility.

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Class average for Exam I 70

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  1. Class average for Exam I 70

  2. Fe3+(aq) + 3 OH-(aq) Fe(OH)3 [Fe3+][OH-]3 = 1.1 x 10-36 [y][3y]3 = 1.1 x 10-36 If there is another source of OH- (NaOH) that provides a higher [OH-] then that is the value of [OH-] to be used.

  3. pH and solubility

  4. CaCO3(s) + H3O+(aq) Ca2+(aq) + HCO3-(aq) + H2O(l)

  5. CaCO3(s) + H3O+(aq) Ca2+(aq) + HCO3-(aq) + H2O(l) Net ionic equation.

  6. CaCO3(s) + H3O+(aq) Ca2+(aq) + HCO3-(aq) + H2O(l) CaCO3 calcium carbonate, present in both limestone and marble.

  7. CaCO3(s) + H3O+(aq) Ca2+(aq) + HCO3-(aq) + H2O(l) CaCO3(s) + H2O(l) Ca2+(aq) + CO32-(aq)

  8. Ksp = [Ca2+][CO32-] CaCO3(s) + H3O+(aq) Ca2+(aq) + HCO3-(aq) + H2O(l) CaCO3(s) + H2O(l) Ca2+(aq) + CO32-(aq) CO32-(aq) + H3O+(aq) H2O(l) + HCO3-(aq)

  9. Ksp = [Ca2+][CO32-] CaCO3(s) + H3O+(aq) Ca2+(aq) + HCO3-(aq) + H2O(l) CaCO3(s) + H2O(l) Ca2+(aq) + CO32-(aq) CO32-(aq) + H3O+(aq) H2O(l) + HCO3-(aq) Any reaction favoring the formation of HCO3- favors the solution of a solid carbonate .

  10. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq)

  11. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp

  12. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17

  13. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 Increase solubility of Zn(OH)2 by lowering pH.

  14. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 Increase solubility of Zn(OH)2 by lowering pH. Removal of product, OH-, shifts equilibrium to right.

  15. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 7

  16. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 7 [Zn2+] = y

  17. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 7 [Zn2+] = y (y)(2y)2 = Ksp

  18. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 7 [Zn2+] = y (y)(2y)2 = Ksp = 4y3 = 4.5 x 10-17

  19. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 7 [Zn2+] = y (y)(2y)2 = Ksp = 4y3 = 4.5 x 10-17 [Zn2+] = 2.2 x 10-6 M [OH-] = 4.4 x 10-6 M

  20. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 6 buffered [Zn2+] = y pH = 6, [H3O+] = 10-6 Kw [OH-] = [H3O+]

  21. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [Zn2+] = ? @ pH = 6 buffered [Zn2+] = y pH = 6, [H3O+] = 10-6 Kw 1 x 10-14 = [OH-] = = 10-8 [H3O+] 10-6

  22. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [OH-] = 1 x 10-8 (y)(1 x 10-8)2 = 4.5 x 10-17

  23. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [OH-] = 1 x 10-8 (y)(1 x 10-8)2 = 4.5 x 10-17 4.5 x 10-17 y = 1 x 10-16

  24. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [OH-] = 1 x 10-8 (y)(1 x 10-8)2 = 4.5 x 10-17 4.5 x 10-17 y = = 4.5 x 10-1 1 x 10-16

  25. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 [OH-] = 1 x 10-8 (y)(1 x 10-8)2 = 4.5 x 10-17 4.5 x 10-17 y = = 4.5 x 10-1 1 x 10-16 [Zn2+] = 0.45 M

  26. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 pH = 7 [Zn2+] = 0.0000022 M [Zn2+] = 0.45 M pH = 6

  27. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 pH = 7 [Zn2+] = 0.0000022 M [OH-] = 2[Zn2+] [Zn2+] = 0.45 M pH = 6

  28. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 pH = 7 [Zn2+] = 0.0000022 M [OH-] = 2[Zn2+] = 4.4 x 10-6 M [Zn2+] = 0.45 M pH = 6

  29. Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq) [Zn2+][OH-]2 = Ksp = 4.5 x 10-17 pH = 8.6 [Zn2+] = 0.0000022 M [OH-] = 2[Zn2+] = 4.4 x 10-6 M [Zn2+] = 0.45 M pH = 6

  30. Solubility of salts of weak acids

  31. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq)

  32. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) Reduce pH, increase [H3O+]

  33. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) Reduce pH, increase [H3O+] Increase [H3O+] : equilibrium

  34. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) NaA(s) Na+(aq) + A-(aq) conjugate base

  35. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) NaA(s) Na+(aq) + A-(aq) A-(aq) + H3O+(aq) HA(aq) + H2O(l)

  36. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) NaA(s) Na+(aq) + A-(aq) A-(aq) + H3O+(aq) HA(aq) + H2O(l) Reduce pH, increase [H3O+]

  37. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) NaA(s) Na+(aq) + A-(aq) A-(aq) + H3O+(aq) HA(aq) + H2O(l) Reduce pH, increase [H3O+], reduce [A-]

  38. Solubility of salts of weak acids HA(aq) + H2O(l) H3O+(aq) + A-(aq) NaA(s) Na+(aq) + A-(aq) A-(aq) + H3O+(aq) HA(aq) + H2O(l) Reduce pH, increase [H3O+], reduce [A-], increase [Na+]

  39. Using common ions to separate mixtures of ions.

  40. Using common ions to separate mixtures of ions. Separating ions which share a group is difficult - they have very similar chemistries.

  41. Using common ions to separate mixtures of ions. I II VII Na+ Ca2+ Cl- K+ Ba2+ I-

  42. M1X M1+ + X- M2X M2+ + X-

  43. M1X M1+ + X- M2X M2+ + X- If the solution is not saturated for either M1X or M2X, there will be no solid present.

  44. M1X M1+ + X- M2X M2+ + X- As [X-] is increased, at some point precipitation will occur.

  45. M1X M1+ + X- M2X M2+ + X- If Ksp for M1X and Ksp for M2X differ by a large enough amount, one will precipitate and the other will remain in solution.

  46. CaF2(s) Ca2+(aq) + 2 F-(aq) BaF2(s) Ba2+(aq) + 2 F-(aq)

  47. CaF2(s) Ca2+(aq) + 2 F-(aq) BaF2(s) Ba2+(aq) + 2 F-(aq) CaF2Ksp = 3.9 x 10-11 BaF2Ksp = 1.7 x 10-6

  48. CaF2(s) Ca2+(aq) + 2 F-(aq) BaF2(s) Ba2+(aq) + 2 F-(aq) CaF2Ksp = 3.9 x 10-11 BaF2Ksp = 1.7 x 10-6 Q < Ksp no precipitate

  49. CaF2(s) Ca2+(aq) + 2 F-(aq) BaF2(s) Ba2+(aq) + 2 F-(aq) CaF2Ksp = 3.9 x 10-11 BaF2Ksp = 1.7 x 10-6 Q = [Ba2+][F-]2 < 1.7 x 10-6

  50. CaF2(s) Ca2+(aq) + 2 F-(aq) BaF2(s) Ba2+(aq) + 2 F-(aq) CaF2Ksp = 3.9 x 10-11 BaF2Ksp = 1.7 x 10-6 Q = [Ba2+][F-]2 < 1.7 x 10-6 Q < Ksp no precipitate

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