Questions from Previous Chemistry 116 Exams

Solubility Equilibria

  1. Select the statement below that is correct.

    1. All compounds of carbonate (CO32-) phosphate (PO43-) and sulfide (S2-) are soluble.
    2. All compounds of nitrate (NO3-) and chlorate (ClO3-) are soluble.
    3. All compounds of hydroxide (OH-) are soluble.
    4. All compounds of the halogen ions (e. g. Cl-, Br-, I-) are insoluble.
    5. No response above is correct.

  2. Addition of sodium bromide, a very soluble salt, to a saturated solution of silver bromide, a slightly soluble salt, would cause:

    1. the concentrations of silver ion, bromide ion and silver bromide to increase.
    2. the concentration of bromide ion to increase and the concentration of silver ion to decrease.
    3. the concentration of bromide ion to decrease and the concentration of silver ion to increase.
    4. the concentration of bromide ion to decrease and the concentration of silver bromide to increase.

  3. Addition of hydrochloric acid to a saturated solution of cadmium hydroxide (Cd(OH)2, Ksp = 2.5 x 10-14) in water would cause:

    1. the solubility of cadmium hydroxide to decrease.
    2. the OH- concentration to decrease and the Cd2+ concentration to increase.
    3. the concentrations of both Cd2+ and OH- to decrease.
    4. the concentrations of both Cd2+ and OH- to increase.
    5. no change in the solubility of Cd(OH)2.

  4. Given the following slightly soluble salts and solubility-product constants, which salt would be most soluble in pure water?

    1. AgCl: Ksp = 1.8 x 10-10.
    2. AgBr: Ksp = 5.0 x 10-15.
    3. AgI: Ksp = 8.3 x 10-17.
    4. AuCl: Ksp = 2.0 x 10-13.

  5. The solubility of gold chloride (AuCl3) in pure water is 1.0 x 10-6 moles per liter. Calculate the solubility product constant of gold chloride in water.

  6. Calculate the molar solubility of cadmium hydroxide (Cd(OH)2) in pure water. For cadmium hydroxide, Ksp = 2.5 x 10-14.

  7. Calculate the molar solubility of cupric hydroxide (Cu(OH)2, Ksp = 2.2 x 10-20) in a solution buffered at pH 8.

  8. Assume a solution containing 0.01 M stannous sulfide (SnS, Ksp = 1.0 x 10-25) and 0.01 M manganese sulfide (MnS, Ksp = 3.0 x 10-15). If sulfide ion (S2-) concentration is increased gradually without dilution of the solution, what will be the molar concentration of Sn2+ ion when manganese sulfide first starts to precipitate?

  9. Which of the following statements is correct?

    1. Most salts of alkali metal ions (K+, Na+), most nitrates, most sulfides and most hydroxides are soluble in water.
    2. Most salts of alkali metal ions (K+, Na+) and most nitrates are insoluble in water and most sulfides and most hydroxides are soluble in water.
    3. Most salts of alkali metal ions (K+, Na+) and most nitrates are soluble in water and most sulfides and most hydroxides are insoluble in water.
    4. Most salts of alkali metal ions (K+, Na+) and most sulfides are insoluble in water and and most nitrates and most hydroxides are soluble in water.
    5. Most salts of alkali metal ions (K+, Na+), most nitrates, most sulfides and most hydroxides are insoluble in water.

  10. Which of the following salts is least soluble in otherwise pure water?

    1. AgCl, Ksp = 1.8 x 10-10
    2. AuCl, Ksp = 2.0 x 10-13
    3. AgI, Ksp = 8.3 x 10-17
    4. AgBr, Ksp = 5.0 x 10-15
    5. CuBr, Ksp = 5.3 x 10-9

  11. Addition of silver nitrate (AgNO3) to a saturated solution of silver chloride (Ksp = 1.8 x 10-10) would cause:

    1. the chloride ion concentration to be larger than that in the saturated solution.
    2. the chloride ion concentration to be smaller than that in the saturated solution.
    3. the chloride ion and silver ion concentrations to be larger than that in the saturated solution.
    4. the chloride ion and silver ion concentrations to be smaller than that in the saturated solution.
    5. no change in the chloride ion concentration.

  12. Addition of solid silver chloride to a saturated solution of silver chloride (Ksp = 1.8 x 10-10) would cause:

    1. the chloride ion concentration to be larger than that in the saturated solution.
    2. no change in the chloride ion concentration.
    3. the chloride ion and silver ion concentrations to be larger than that in the saturated solution.
    4. the chloride ion and silver ion concentrations to be smaller than that in the saturated solution.
    5. the chloride ion concentration to be smaller than that in the saturated solution.

  13. The solubility of gold chloride (AuCl3 <=> Au3+ + 3Cl- ) in water is 1.04 x 10-6 mol/L. Calculate the value of the solubility-product constant, Ksp, for gold chloride.

  14. The solubility-product constant for lead iodide (PbI2 <=> Pb2+ + 2I- ) is Ksp = 7.1 x 10-9. Calculate the molar solubility of lead iodide in otherwise pure water.

  15. Calculate the molar solubility of lead iodide (PbI2 <=> Pb2+ + 2I- , Ksp = 7.1 x 10-9) in a solution containing 0.10 M potassium iodide (KI), a very soluble salt.

  16. What mimimum hydronium ion concentration (M) would be needed to prevent precipitation of cupric hydroxide (Cu(OH)2 <=> Cu2+ + 2OH- , Ksp = 2.2 x 10-20) from a solution containing 0.010 M Cu2+ ion?

  17. Which of the following diagrams represents a snapshot of a very small portion of THE SOLUTION in a beaker containing silver chloride, AgCl, in water at equilibrium? Note that the solvent molecules (i.e., H2O) are not shown for clarity.

    AgCl (s) <=> Ag+ (aq) + Cl- (aq)

  18. Calculate the solubility (in M) of MgF2 (Ksp = 6.5 x 10-9) in water.

  19. Calculate the solubility (in M) of AgBr (Ksp = 5.0 x 10-15) in a solution that initially contains 0.25 M NaBr.

  20. Which of the following best describes what will happen when a solution of AgNO3 is slowly added to a saturated solution of silver acetate, CH3COOAg, without changing the volume significantly?

    CH3COOAg (s) <=> CH3COO- (aq) + Ag+ (aq)

    1. Some of the solid silver acetate will dissolve.
    2. The concentration of acetate ion will increase.
    3. Some solid silver acetate will precipitate.
    4. The concentrations of acetate ion and silver ion will both increase.
    5. The addition of AgNO3 will have no effect on the position of the equilibrium.

  21. Which one of the following groups contains only salts that are expected to be soluble in water?

    1. ZnS, KNO3, CoS, PbCrO4
    2. NaCl, KNO3, Zn(NO3)2, MgSO4
    3. Ca3(PO4)2, Cr(OH)3, NaCl, ZnS
    4. AgOH, Cu(OH)2, KCl, NaI
    5. A correct response is not given.

  22. Which of the following groups contains only salts that are expected to be highly soluble in water?

    1. NaCl, KNO3, ZnS, PbCrO4,
    2. NaCl, KNO3, Zn(NO3)2 , Na2S.
    3. ZnS, PbCrO4, Ca3(PO4)2, Cr(OH)3
    4. ZnS, KNO3 , PbCrO4, CoS.
    5. A correct response is not given.

  23. Which of the following groups contains only salts that are expected to be slightly soluble or insoluble in water?

    1. NaCl, KNO3, ZnS, PbCrO4
    2. NaCl, KNO3, Zn(NO3)2 , Na2S.
    3. ZnS, PbCrO4, Ca3(PO4)2, Cr(OH)3
    4. ZnS, KNO3 , PbCrO4, CoS.
    5. A correct response is not given.

    Use the following reaction to answer the next four questions:

    Ca3(PO4)2 <=> 3 Ca2+ + 2 PO43-

  24. What is the correct expression for the solubility product constant for calcium phosphate?

    1. Ksp = [Ca2+] [PO43-]
    2. Ksp = [Ca2+]2 [PO43-]2
    3. Ksp = [Ca2+]2 [PO43-]2
    4. Ksp = [Ca2+]3 [PO43-]2
    5. The correct response is not given.

  25. What is the correct relationship between the solubility of calcium phosphate in pure water, C0 (Ca3(PO4)2), and the equilibrium concentration of calcium ion, [Ca2+]?

    1. [Ca2+] = 3C0 (Ca3(PO4)2)
    2. [Ca2+] = 2C0 (Ca3(PO4)2)
    3. [Ca2+] = (1/3)C0 (Ca3(PO4)2)
    4. [Ca2+] = (3/2)C0 (Ca3(PO4)2)
    5. The correct response is not given.

  26. Addition of calcium nitrate, (Ca(NO3)2), to a saturated solution of calcium phosphate would:

    1. have no effect on the solubility of calcium phosphate.
    2. cause the solubility of calcium phosphate to decrease.
    3. cause the solubility of calcium phosphate to increase.
    4. cause unpredictable changes in the solubility of calcium phosphate.
    5. The correct response is not given.

  27. Recognizing that the phosphate ion is a strong Bronsted base, we can accurately predict that addition of hydrochloric acid to a saturated solution of calcium phosphate would:

    1. have no effect on the solubility of calcium phosphate.
    2. cause the solubility of calcium phosphate to decrease.
    3. cause the solubility of calcium phosphate to increase.
    4. cause unpredictable changes in the solubility of calcium phosphate.
    5. The correct response is not given.

  28. The solubility of silver sulfate (Ag2SO4 <=> 2 Ag+ + SO42-) in pure water is 0.0152 mol/L. Calculate the solubility product constant, Ksp, for silver sulfate.

  29. The solubility product constant for lead chloride (PbCl2 <=> Pb2+ + 2 Cl-) is Ksp = 1.6 x 10-5. Calculate the molar solubility of lead chloride in pure water.

  30. Calculate the molar solubility of gold chloride (AuCl3, Ksp = 3.2 x 10-25 ) in a solution containing 1.0 x 10-5 M chloride ion.

  31. Calculate the molar solubility of manganese hydroxide (Mn(OH)2, Ksp = 2.0 x 10-13 ) in a solution buffered at pH = 9.00.

  32. What happens to the concentration of the Pb2+ and SO42- ions in a saturated solution of PbSO4 in contact with solid PbSO4 when the solution evaporates to half of its original volume?

    1. The concentrations of Pb2+ and SO42- increase.
    2. The concentrations of Pb2+ and SO42- decrease.
    3. The concentrations of Pb2+ and SO42- remain the same.
    4. It is impossible to say unless we know the Ksp of PbSO4.

  33. Which of the following contains TWO anions that form soluble salts with most metal ions and TWO anions that form insoluble salts with most metal ions?

    1. Sulfate, hydroxide, chromate, sulfide
    2. Nitrate, hydroxide, chromate, sulfide
    3. Chloride, hydroxide, chromate, sulfide
    4. Nitrate, chloride, hydroxide, sulfide

  34. Consider an aqueous solution that contains 0.10 M each of Pb2+, Hg2+ and Ni2+. If a solution containing 2.0 x 10-20 M S2- is added to the solution containing the metal ions, which sulfides will precipitate from the solution?

    PbS: Ksp = 8.0 x 10-28; HgS: Ksp = 4 x 10-53; NiS: Ksp = 3.2 x 10-19

    1. PbS, HgS and NiS
    2. PbS and HgS
    3. HgS and NiS
    4. NiS only
    5. HgS only

  35. How much (in g) barium sulfate (BaSO4, MW=233.39) will dissolve in 500 mL of water. For BaSO4: Ksp = 1.1 x 10-10.

  36. Which anions below are expected to form soluble salts with all metal ions?

    1. S2-, OH-, NO3-
    2. S2-, Cl-, NO3-
    3. NO3-, ClO3-, ClO4-
    4. CO32-, PO43-, S2-
    5. No response is correct.

  37. Which anions below are expected to form insoluble compounds with most metal ions except alkali metal ions and ammonium ion?

    1. S2-, OH-, NO3-
    2. S2-, Cl-, NO3-
    3. NO3-, ClO3-, ClO4-
    4. CO32-, PO43-, S2-
    5. No response is correct.

  38. Which of the following salts is the most soluble in pure water?

    1. AgBr: Ksp = 7.7 x 10-13
    2. AgI: Ksp = 8.3 x 10-17
    3. AgCl: Ksp = 1.6 x 10-10
    4. SrSO4: Ksp = 3.8 x 10-7
    5. More information is needed to answer the question.

  39. Addition of solid silver sulfate (Ag2SO4, Ksp = 1.4 x 10-5) to a solution that is already saturated in silver sulfate will cause:

    1. no change in Ag+ or SO42- concentrations.
    2. more silver sulfate to dissolve.
    3. some silver sulfate to precipitate from solution.
    4. the silver ion concentration to increase and the sulfate ion concentration to decrease.
    5. No response is correct.

  40. The solubility of silver chromate (Ag2CrO4) in water is 1.3 x 10-4 mol/L; what is the solubility product constant for silver chromate?

  41. Calculate the solubility of Ag4(FeCN)6 in water assuming no other interfering equilibria.

    Ag4Fe(CN)6 <=> 4 Ag+ + Fe(CN)64-, Ksp = 1.6 x 10-41

  42. Calculate the solubility of aluminum hydroxide (Al(OH)3, Ksp = 1.0 x 10-33) in a solution buffered at pH 11.

  43. What hydroxide ion concentration would be required to start precipitation of manganese hydroxide from a solution that is 0.0031 mol/L in Mn2+. For Mn(OH)2, Ksp = 4.6 x 10-14.

  44. Milk of magnesia consists of gelatinous Mg(OH)2 (s) and a small amount of water saturated with Mg(OH)2. Calculate the pH of the milk of magnesia found in the drug store. Ksp (Mg(OH)2) = 8.9 x 10-12. You may neglect the dissociation of water.

  45. Gastric juice (i.e., the digestive juice found in our stomach) has a pH of approximately 1.4. Would you expect the solid Mg(OH)2 found in milk of magnesia to be more soluble in gastric juice or in pure water?

  46. Consider a saturated solution of silver bromide, AgBr. If more solid silver bromide were added to this saturated solution, describe what will happen to:

    1. the concentration of Ag+.

    2. the concentration of Br-.

    3. the solubility of AgBr.

  47. Which one of the following groups of ions generally does NOT form soluble salts?

    1. sodium (Na+), potassium (K+) and ammonium (NH4+)
    2. sulfides (S2-), oxides (O2-) and hydroxides (OH-)
    3. nitrates (NO3-) and sulfates (SO42-)
    4. chlorides (Cl-), and bromides (Br-)
    5. all of these generally form insoluble salts

  48. Which one of the following groups of salts are ALL expected to be soluble in water?

    1. NaCl, K2SO4, Zn(NO3)2
    2. NaCl, K2SO4, ZnS
    3. PbCrO4, ZnS, (NH4)2S
    4. NaOH, K2SO4, Zn(OH)2
    5. all of these salts are soluble in water

  49. Which one of the following is the correct expression for the solubility product constant for Ca3(PO4)2?

    1. Ksp = 3[Ca2+] 2[PO43-]
    2. Ksp = (3[Ca2+])3(2[PO43-])2
    3. Ksp = (2[Ca2+])3(3[PO43-])2
    4. Ksp = [Ca2+]3[PO43-]2
    5. Ksp = [Ca2+]2[PO43-]3

  50. Calculate the molar solubility of silver carbonate, Ag2CO3, in pure water if the solubility product constant for Ag2CO3 is 8.1 x 10-12.

    1. 8.1 x 10-12 M
    2. 2.8 x 10-6 M
    3. 1.3 x 10-4 M
    4. 2.6 x 10-4 M
    5. 3.4 x 10-3 M

  51. Which of the following hydroxides is LEAST soluble in water?

    1. Ba(OH)2 : Ksp = 5.0 x 10-3
    2. Ca(OH)2 : Ksp = 5.5 x 10-6
    3. Cd(OH)2 : Ksp = 2.5 x 10-14
    4. Zn(OH)2 : Ksp = 1.2 x 10-17
    5. Fe(OH)3 : Ksp = 4.0 x 10-38

  52. Calculate the sulfide ion concentration that is required to just start precipitation of CoS from a solution that is 0.10 M in Co2+. For CoS : Ksp = 4 x 10-21.

    1. [S2-] = 4 x 10-21 M
    2. [S2-] = 4 x 10-20 M
    3. [S2-] = 2 x 10-10 M
    4. [S2-] = 6 x 10-10 M
    5. [S2-] = 1 x 10-7 M

  53. Which of the following groups contains two salts that are soluble in water and two salts that are slightly soluble or insoluble in water?

    1. AgCl, NaCl, NaNO3, Pb(NO3)2
    2. AgCl, NaCl, Ca(NO3)2, ZnS
    3. NaNO3, Ba(NO3)2, Ca(NO3)2, ZnS
    4. NaNO3, Ba(NO3)2, Ca(NO3)2, ZnS
    5. ZnS, PbCrO4, Sb2S3, Fe(NO3)2

  54. What is the correct expression for the solubility product constant for the reaction,

    Bi2S3 <=> 2 Bi3+ + 3 S2-

    1. Ksp = [Bi3+]2[S2-]3
    2. Ksp = [3 Bi3+]2[2 S2-]3
    3. Ksp = [2 Bi3+]2[3 S2-]3
    4. Ksp = 2[Bi3+]2 + 3[S2-]3

  55. When the base, Al(OH)3, dissolves in pure water, what is the relationship between the solubility, S, and the concentrations of Al3+ and OH-, assuming no complicating reactions.

    1. S = [Al3+] + [OH-]
    2. S = [Al3+] + 3[OH-]
    3. [OH-] = 3 S, [Al3+] = S
    4. S = [Al3+] = 3 [OH-]

  56. The solubility of silver sulfide (Ag2S) in pure water is 2.5 x 10-17 M. What is the solubility product constant for silver sulfide?

    1. 6.3 x 10-34
    2. 2.5 x 10-17
    3. 6.2 x 10-50
    4. 1.6 x 10-50

  57. The solubility product constant of calcium fluoride, (CaF2), in water is 4.0 x 10-11. What is the molar solubility of calcium fluoride in water?

    1. 4.0 x 10-11 M
    2. 2.2 x 10-4 M
    3. 6.3 x 10-6 M
    4. 2.5 x 10-5 M

  58. The solubility product constant for cobaltic hydroxide, [Co(OH)3], is 1.6 x 10-44. What is the solubility of cobaltic hydroxide in a solution buffered at pH 8?

    1. 1.6 x 10-26 M
    2. 1.3 x 10-22 M
    3. 1.6 x 10-20 M
    4. 1.6 x 10-44 M

  59. What Pb2+ ion concentration could exist in a solution in which the sulfide ion concentration is just high enough to start precipitation of cobalt sulfide from a solution that contains 0.20 M Co2+? [PbS: Ksp = 8 x 10-28; CoS: Ksp = 4 x 10-21]

    1. 2 x 10-7
    2. 8 x 10-7
    3. 8 x 10-28
    4. 4 x 10-8

  60. Write the solubility product equilibrium constant expression for lead phosphate, Pb3(PO4)2.

  61. A Chemistry 116 student was charged with the task of measuring the Ksp of silver bromide, AgBr. The student went into the lab and determined that 1.1 milligrams of AgBr would dissolve in 10.0 L of pure water. Using this information, calculate the Ksp of AgBr.

  62. Milk of magnesia consists of gelatinous Mg(OH)2 (s) (Ksp = 8.9 x 10-12) and a small amount of water saturated with Mg(OH)2. Explain what would happen to the solubility of Mg(OH)2 when each of the following reagents were added to such a solution.

    1. magnesium nitrate, Mg(NO3)2

    2. sodium hydroxide, NaOH

    3. hydrochloric acid, HCl

    4. sodium nitrate, NaNO3

  63. Calculate the solubility of barium sulfate, BaSO4, in a solution that has been prepared by dissolving 0.15 moles of sodium sulfate, Na2SO4, in 500 mL of pure water. Ksp(BaSO4) = 1.1 x 10-10.

  64. In Chapter 18 of your text we studied solubility. Which of the following statements is correct?

    1. Insoluble salts will not dissolve at all in water.
    2. Solubility of a salt depends on the temperature of the system.
    3. Soluble salts will dissolve in all proportions.
    4. The solubility of AgCl is not affected by the addition of NaCl.

  65. The solubility of Ca3(PO4)2 is 2.57 x 10-6 M. Calculate the Ksp for this salt.

  66. What is the solubility in mol/L of insoluble SnS (Ksp = 1.01 x 10-26) in a solution containing 0.100 M Na2S, a soluble salt?

  67. Addition of HCl to a saturated solution of barium hydroxide, Ba(OH)2, Ksp = 5.0 x 10-3) would cause:

    1. the solubility of Ba(OH)2 to decrease.
    2. the OH- concentration to decrease and the Ba2+ concentration to increase.
    3. the OH- concentration to increase and the Ba2+ concentration to decrease.
    4. the concentrations of both Ba2+ and OH- to increase.
    5. no change in the solubility of Ba(OH)2.

  68. Calculate the molar solubility of silver iodide, AgI, in a solution containing 0.20 M sodium iodide, NaI. For AgI, Ksp = 8.3 x 10-17.

  69. Which of the following salts would be MOST SOLUBLE in pure water?

    1. AuI, Ksp = 1.6 x 10-23
    2. CuCN, Ksp = 3.2 x 10-20
    3. MnS, Ksp = 3.0 x 10-15
    4. AgCl, Ksp = 1.8 x 10-10
    5. TlBr, Ksp = 3.4 x 10-6

  70. An aqueous solution contains 0.10 M Ag+, 0.10 M Cd2+ and 0.10 M Mn2+. If sulfide ion, S2-, is slowly added to this solution, which of the following salts will precipitate FIRST?

    1. Ag2S, Ksp = 6.3 x 10-50
    2. CdS, Ksp = 8.0 x 10-27
    3. MnS, Ksp = 3.0 x 10-15
    4. All of these salts will precipitate at the same time.
    5. It is impossible to tell.

  71. Calculate the solubility (in M) of lead sulfate (PbSO4, Ksp = 1.6 x 10-8) in water.

    1. 2.6 x 10-16
    2. 1.6 x 10-8
    3. 6.3 x 10-5
    4. 1.3 x 10-4
    5. 3.5 x 10-3

  72. Which of the following diagrams represents a snapshot of a very small portion of THE SOLUTION in a beaker containing a saturated solution of calcium fluoride (CaF2) in water? Note that the solvent molecules (i.e., H2O) are not shown for clarity.

    CaF2 (s) <==> Ca2+ (aq) + 2 F- (aq)

  73. Assuming solutions saturated in each of the following salts, which would have the largest concentration of silver ion (Ag+)?

    1. AgCl (Ksp = 1.8 x 10-10) in pure water
    2. AgBr (Ksp = 5.0 x 10-13) in pure water
    3. AgI (Ksp = 1.8 x 10-17) in pure water
    4. AgCl (Ksp = 1.8 x 10-10) in 0.1 M sodium chloride

  74. Given a saturated solution of aluminum hydroxide (Al(OH)3, Ksp = 1.3 x 10-33), addition of which of the following would have NO EFFECT on the solubility of Al(OH)3?

    1. Al(NO3)3
    2. NaOH
    3. NaNO3
    4. HCl

  75. Which of the following statements is TRUE about a saturated solution of silver chloride, AgCl? For AgCl, Ksp = 1.8 x 10-10.

    1. All of the silver chloride that has dissolved has completely dissociated to produce Ag+(aq) and Cl-(aq) ions.
    2. The solution would not conduct electricity.
    3. There are no Ag+(aq) or Cl-(aq) ions present in the solution.
    4. There is undissociated AgCl present in the solution.

  76. Consider the following solubility equilibria,

    Zn(OH)2(s) <=> Zn2+(aq) + 2OH-(aq)

    Cu(OH)2(s) <=> Cu2+(aq) + 2OH-(aq)

    Which of the following reagents, when added to a solid mixture containing both Zn(OH)2(s) and Cu(OH)2(s), would be MOST EFFECTIVE at dissolving both solids?

    1. Cu(NO3)2(aq)
    2. Zn(NO3)2(aq)
    3. NaOH(aq)
    4. CH3CO2H (acetic acid)
    5. HCl

  77. Which of the following describes what happens to the concentrations of Ni2+ and OH-, and the pH of the solution when solid nickel hydroxide (Ni(OH)2) is added to a saturated solution of Ni(OH)2 in water?


    		concentration of Ni2+concentration of OH-pH
    (a)no changeno changeno change
    (b)increasesdecreasesdecreases
    (c)no changeno changeincreases
    (d)decreasesdecreasesdecreases
    (e)increasesincreasesno change

  78. For a particular slightly soluble salt, the value of Ksp was determined in water at several different temperatures. A plot of ln Ksp versus 1/T gives a straight line with a slope equal to -5827 and a y-intercept equal to 15.25. Under standard conditions, the dissolution of the slightly soluble salt in water is:

    1. endothermic.
    2. exothermic.
    3. neither exothermic nor endothermic.
    4. both exothermic and endothermic.
    5. It is impossible to tell.

Answers

  1. B or E
  2. B
  3. B
  4. A
  5. 2.7 x 10-23
  6. 1.8 x 10-5
  7. 2.2 x 10-8
  8. 3.3 x 10-13
  9. C
  10. C
  11. B
  12. B
  13. 3.16 x 10-23
  14. 1.2 x 10-3
  15. 7.1 x 10-7
  16. 6.7 x 10-6
  17. E
  18. 1.2 x 10-3
  19. 2.0 x 10-14
  20. C
  21. B
  22. B
  23. C
  24. D
  25. A
  26. B
  27. C
  28. 1.4 x 10-5
  29. 0.016
  30. 3.2 x 10-10
  31. 2.0 x 10-3
  32. C
  33. D
  34. B
  35. 1.2 x 10-3
  36. C
  37. D
  38. D
  39. A
  40. 8.8 x 10-12
  41. 2.3 x 10-9
  42. 1.0 x 10-24
  43. 3.9 x 10-6
  44. 10.4
  45. Mg(OH)2 should be more soluble in gastric juice. Consider the following equilibria:

     Mg(OH)2 (s)  <=>  Mg2+  +  2 OH-
 H3O+  +  OH-  <=>  2 H2O

    The acid in gastric juice reacts with the strong base, OH-, to produce water. This will shift the first equilibrium to the right causing more solid Mg(OH)2 to dissolve.

    1. Nothing. The solution is saturated so no more solid will dissolve.

    2. Nothing. The solution is saturated so no more solid will dissolve.

    3. Nothing. The solution is saturated so no more salt will dissolve. The solubility will be unaffected.

  47. B
  48. A
  49. D
  50. C
  51. E
  52. B
  53. B
  54. A
  55. C
  56. C
  57. B
  58. A
  59. D
  60. Ksp = [Pb2+]3[PO43-]2
  61. 3.5 x 10-13
    1. Addition of magnesium nitrate, a soluble salt, would decrease the solubility of magnesium hydroxide. The reaction will shift to the left to reestablish equilibrium.

    2. Addition of sodium hydroxide, a soluble salt, would decrease the solubility of magnesium hydroxide. The reaction will shift to the left to reestablish equilibrium.

    3. Addition of hydrochloric acid will increase the solubility of magnesium hydroxide (HCl, a strong acid, reacts with hydroxide ion, a strong base). The reaction will shift to the right to reestablish equilibrium.

    4. Addition of sodium nitrate will have NO EFFECT since it does not contain any common ions, and it is neither an acid or a base.

  63. 3.7 x 10-10
  64. B
  65. 1.21 x 10-26
  66. 1.01 x 10-25
  67. B
  68. 4.2 x 10-16
  69. E
  70. A
  71. D
  72. D
  73. A
  74. C
  75. A
  76. E
  77. A
  78. A