CHEM 12 Unit 3 Review package (solubility)

CHEM 12 Unit 3 Review package (solubility) 1. Which of the following combinations would form an ionic solid? A. Metalloid - metal B. Metal non-metal C. Metalloid metalloid D. Non-metal non-metal 2. Which of the following compounds would form a molecular solution when dissolved in water? A. HCl B. NaCl C. NaHCO 3 D. C 12 H 22 O 11 3. A 3.0L solution of NiCl 2 is found to have a chloride concentration of 0.60M. The concentration of nickel(ii) ions in this solution is A. 0.30M B. 0.60M C. 0.90M D. 1.2M 4. A solution is prepared by dissolving 0.020 mol Zn(NO 3 ) 2 in enough water to make 250.0mL of solution. The concentration of nitrate ions in this solution is: A. 0.16M B. 0.020M C. 0.080M D. 0.040M 5. Which of the following compounds is the most soluble? A. AgBr B. CaCO 3 C. NH 4 Cl D. Fe(OH) 3 6. Which of the following salts has the lowest solubility in water? A. MgS B. FeCl 2 C. ZnSO 4 D. Ca 3 (PO 4 ) 2 7. Which of the following has low solubility at room temperature? A. ZnCl 2 B. ZnSO 4 C. ZnCO 3 D. Zn(NO 3 ) 2

8. Which of the following compounds is the least soluble? A. CaS B. AlCl 3 C. Sr(OH) 2 D. Ag 2 SO 4 9. Consider the following data: ZnC 2 O 4, SrC 2 O 4, CuC 2 O 4, and CaC 2 O 4 all have K sp values of approximately 1 x 10-9. Which compound has the lowest solubility in a solution of 0.1M Ca(NO 3 ) 2? A. CaC 2 O 4 B. CuC 2 O 4 C. SrC 2 O 4 D. ZnC 2 O 4 10. A cation that forms a ppt when added to 0.1M K 2 SO 4 but not when added to 0.1M Na 2 S is A. Cu + B. Sr +2 C. Cu +2 D. Ag + 11. Which of the following solutes could dissolve to produce at least 0.1M SO 3-2 in solution at 25 o C? A. FeSO 3 B. ZnSO 3 C. Na 2 SO 3 D. Al 2 (SO 3 ) 3 12. A solution is known to contain one of these ions: Mg +2, Ca +2, Sr +2, Be +2. Mixing samples of the solution with various reagents gives the following data: Reagent Na 2 S Na 2 SO 4 NaOH Result No ppt Ppt No ppt From this data, the ion must be: A. Ca +2 B. Be +2 C. Sr +2 D. Mg +2 13. A student is given 3 beakers, each containing 100mL of solution. The first contains 0.20M CaS; 0.20M CuSO 4 ; the third contains 0.20M Ba(OH) 2. The student is asked to select 2 of the solutions which, when combined, result in a mixture containing only a single precipitate. A) Which solutions should the student use? (1 mark) B) Write a net ionic equation for the precipitation reaction (1 mark)

14. Which of the following is the net ionic equation for the reaction that occurs when 0.2M Pb(NO 3 ) 2 is mixed with 0.2M NaI? A. PbI 2(s) Pb +2 (aq) + 2I - (aq) B. Pb +2 (aq) + 2I - (aq) PbI 2(s) C. Na + (aq) + NO 3 - (aq) NaNO 3 (s) D. NaNO 3 (s) Na + (aq) + NO 3 - (aq) 15. Write the net ionic equation(s) for the reaction(s) when equal volumes of 0.2M Ba(OH) 2 and 0.2M Fe 2 (SO 4 ) 3 are mixed (2 marks) 16. When equal volumes of 0.2M CaS and 0.2M Sr(OH) 2 are mixed A. No precipitate will form B. A precipitate of SrS will form C. A precipitate of Ca(OH) 2 will form D. Precipitates of both Ca(OH) 2 and SrS will form. 17. In which of the following will AgBr be most soluble? A. pure water B. 0.10M KBr C. 0.10M CaBr 2 D. 0.10M AgNO 3 18. Which of the following solutions could be used to separate Ca +2 (aq) from Pb +2 (aq) in a solution containing both cations? A. ZnCl 2 (aq) B. Ba(OH) 2 (aq) C. MgSO 4 (aq) D. Na 2 CO 3 (aq) 19. An unknown solution is known to contain one of the following cations: Ca +2, Ba +2, Mg +2, or Pb +2. A student, adding various reagents to separate samples of the unknown solution, obtains the following data: Reagent added NaBr Na 2 SO 4 Na 2 S NaOH Observation No ppt No ppt No ppt ppt From the above data, the unknown solution must contain: A. Mg +2 B. Ca +2 C. Ba +2 D. Pb +2

20. a) Give the formula of an anion that is capable of separating Mg +2 (aq) from Ba +2 (aq) by a precipitation reaction (1 mark) b) Write the net ionic equation for the above precipitation reaction (1 mark) 21. A solution contains SO 4-2 and Cl -. Outline an experimental procedure to remove each ion individually from the solution, and identify the reagents (ions or compounds) used in the procedure. (3 marks) 22. In a qualitative analysis experiment, a student has a solution which contains 0.10M Cl - and 0.10M SO 4-2. a) Write the formula of a compound that could be added to this solution to precipitate the sulphate ion while leaving the chloride ion in solution. (1 mark) b) Write the net ionic equation for the precipitation reaction (1 mark) 23. Which of the following reagents could be used to indicate the presence of Ca +2 in a solution? A. H 2 S B. AgNO 3 C. Na 2 CO 3 D. Ca(CH 3 COO) 2 24. A solution is known to contain Hg 2 +2, Be +2, and Sr +2 ions, each at a concentration of 0.20M. a) What ion could be used to precipitate the Sr +2 while leaving the other two cations in solution? (1 mark) b) Write the net ionic equation for the reaction (1 mark) 25. When equal volumes of 0.2M K 2 CO 3 and 0.2M Na 3 PO 4 are mixed A. No precipitate will form B. A precipitate of K 3 PO 4 will form C. A precipitate of Na 2 CO 3 will form D. Precipitates of both K 3 PO 4 and Na 2 CO 3 will form 26. A solution of Ba(NO 3 ) 2 is added to a solution of Na 2 CO 3, resulting in the formation of a white precipitate that dissolves in HNO 3. a) Write a net ionic equation to represent the formation of the white precipitate (1 mark) b) Explain why the precipitate dissolves in HNO 3 (1 mark)

27. Consider the following equilibrium Ag 2 CrO 4 (s) 2Ag + (aq) + CrO 4-2 (aq) Which of the following procedures will increase the solubility of Ag 2 CrO 4 in a saturated solution of Ag 2 CrO 4? A. Add KI (s) B. Add Na 2 CrO 4 (s) C. Add AgCH 3 COO (s) D. Add more Ag 2 CrO 4 (s) 28. Explain why more Zn(OH) 2 dissolves when 3M HCl is added to a saturated solution of Zn(OH) 2. Provide the appropriate equilibrium equation(s). (3 marks) 29. In an experiment, 0.1M AgNO 3 is added to 0.1M NaCl, resulting in the formation of a white precipitate. When 0.1M NaI is added to this mixture, the white precipitate dissolves and a yellow precipitate forms. a) Write the formula for: i. The white ppt ii. The yellow ppt b) Write a net ionic equation to represent the formation of the more soluble precipitate (1 mark) 30. A 0.50L solution of CuBr 2 contains 0.30 mol of Br -. The ionic concentrations in this solution are: A. [Cu +2 ] = 0.15M, [Br - ] = 0.30M B. [Cu +2 ] = 0.30M, [Br - ] = 0.60M C. [Cu +2 ] = 0.60M, [Br - ] = 0.60M D. [Cu +2 ] = 0.60M, [Br - ] = 1.2 M 31. Describe the equilibrium that exists in a saturated solution of BaSO 4 in contact with some solid residue of BaSO 4. (2 marks) 32. Solubility equilibrium can exist only in a A. Dilute solution B. Saturated solution C. Concentrated solution D. Solution of an ionic substance 33. In order to determine experimentally the solubility of a solute in water, a student must initially prepare A. A saturated solution which is at equilibrium B. A saturated solution which is not at equilibrium C. An unsaturated solution which is at equilibrium D. An unsaturated solution which is not at equilibrium

34. A beaker contains an unsaturated solution and some solid solute. The rate of dissolving of the solid is: A. zero B. equal to the rate of precipitation C. less than the rate of precipitation D. greater than the rate of precipitation 35. For which of the following systems would the equilibrium constant expression be referred to as a K sp expression? A. H 2 O (l) H + (aq) + OH - (aq) B. 2SO 2 (g) + O 2 (g) 2SO 3 (g) C. CaCO 3 (s) Ca +2 (aq) + CO 3-2 (aq) D. CH 3 COOH (aq) CH 3 COO - (aq) + H + (aq) 36. Consider the solubility equilibrium and K sp expression of Ag 2 SO 4 : Ag 2 SO 4 (s) 2Ag + (aq) + SO 4-2 (aq) K sp = [Ag + ] 2 [SO 4-2 ] The [Ag 2 SO 4 (s) ] does not appear in the K sp expression because it is A. Zero B. Constant C. Saturated D. Small enough to disregard 37. The equilibrium equation for AgCl in water is: AgCl (s) Ag + (aq) + Cl - (aq) Which of the following would decrease the solubility of AgCl? A. Add more water B. Add more AgCl (s) C. Add some AgNO 3 (s) D. Evaporate some water. 38. Consider the following equilibrium system: PbCl 2(s) Pb +2 (aq) + 2Cl - (aq) In calculating the value of the equilibrium constant of the above system, one must multiply the [Pb +2 ] by: A. [Cl - ] / 2 B. [Cl - ] 2 C. [2Cl - ] D. [2Cl - ] 2 39. Which of the following compounds is most soluble in water? A. PbCrO 4 K sp = 1.8 x 10-14 B. BaCrO 4 K sp = 2.1 x 10-10 C. CuCrO 4 K sp = 3.6 x 10-6 D. CaCrO 4 K sp = 7.1 x 10-4

40. In a saturated solution of BaCO 3, [CO 3-2 ] = 9.0 x 10-5 M. What is the value of K sp for BaCO 3? A. 8.1 x 10-9 B. 9.0 x 10-5 C. 1.8 x 10-4 D. 9.5 x 10-3 41. The solubility of FeS is 4.6 x 10-4 mol/l. From this information, the K sp of FeS must be: A. 2.1 x 10-7 B. 4.6 x 10-4 C. 9.2 x 10-4 D. 2.1 x 10-2 42. What is the value of K sp for AgCl if its solubility is 1.3 x 10-5 M? A. 4.2 x 10-11 B. 1.7 x 10-10 C. 2.6 x 10-5 D. 1.3 x 10-5 43. If the solubility of Pb(OH) 2 is 0.155g/L, then the concentration of each ion in a saturated solution of Pb(OH) 2 is: A. [Pb +2 ] = 0.155 g/l; [OH - ] = 0.155 g/l B. [Pb +2 ] = 0.052 g/l; [OH - ] = 0.103 g/l C. [Pb +2 ] = 6.43 x 10-4 M; [OH - ] = 1.29 x 10-3 M D. [Pb +2 ] = 6.43 x 10-4 M; [OH - ] = 6.43 x 10-4 M 44. In a 400.0mL saturated solution of PbCl 2, it is found that 0.042 mol of Cl are present. Calculate the value of K sp for PbCl 2. (4 marks) 45. What is the value of K sp for MgF 2 if its solubility is 0.0736 g/l? (4 marks) 46. The K sp of BaSO 4 is 3.1 x 10-9. Therefore, the solubility of BaSO 4 is: A. 9.6 x 10-18 M B. 1.6 x 10-9 M C. 3.1 x 10-9 M D. 5.6 x 10-5 M 47. Calculate the [OH - ] of a saturated solution of Mg(OH) 2 if K sp for Mg(OH) 2 is 1.2 x 10-11 (3 marks). Note: in unit 4 you will use this information to calculate ph 48. Calculate the maximum mass of Ag 2 CrO 4 that can dissolve in 4.0L of water. The K sp of Ag 2 CrO 4 is 1.4 x 10-17 (4 marks) 49. Calculate the mass of SrCO 3 that will dissolve in 2.00L of water to form a saturated solution. The K sp of SrCO 3 is 1.0 x 10-8. (4 marks)

50. Which of the following relationships must be used to calculate the [I - ] that would be needed to just start precipitation of PbI 2 from a solution of Pb(NO 3 ) 2? A. [I - K sp ] = B. [I - +2 [Pb ] ] = +2 [ Pb ] K sp K sp C. [I - ] = + 2 Pb D. [I - +2 ] = K sp [ Pb ] 51. Calculate the maximum mass of Na 2 SO 4 that can remain in 0.600L of a solution in which [Sr +2 ] = 4.0 x 10-3 M. Given: K sp (SrSO 4 ) = 3.8 x 10-7 (4 marks) 52. Determine the maximum [OH - ] that can exist in a solution of 0.20M Cu(NO 3 ) 2 of K sp for Cu(OH) 2 is 1.6 x 10-19? (3 marks) 53. In an experiment designed to determine the K sp of Ag 2 SO 4, a chemist pipettes 25.00mL of a saturated solution of Ag 2 SO 4 into an Erlenmeyer flask, and titrates with 0.102M KSCN. The reaction is as follows: Ag + (aq) + SCN - (aq) AgSCN (s) The endpoint is reached after 15.15mL of the 0.102M KSCN has been added. Using this data, calculate the K sp for Ag 2 SO 4. (5 marks) 54. Explain why the addition of 10mL of 0.5M CaCl 2 to a saturated solution of AgCl will result in more precipitate than the addition of 10mL of 0.5M AgNO 3. Identify the precipitate in your explanation. (2 marks) 55. A student is given a 100.0mL saturated solution of PbCl 2 and is asked to obtain a value for the K sp by first determining the [Cl - ]. In titrating 25.00mL samples of this PbCl 2 (aq) solution the student requires an average of 7.9mL of a 0.100M AgNO 3 solution to precipitate all the Cl -. Use these data to calculate the K sp value for PbCl 2. (4 marks). 56. In an experiment, a student mixes various amounts of AgNO 3 (aq) and MgSO 4 (aq) in two beakers until a precipitate just forms in each. Given the data below, calculate the [SO -2 4 ] that must be present in beaker 2. (4 marks) Eq m [Ag + ] Eq m [SO -2 4 ] Beaker 1 0.025M 0.024M Beaker 2 0.050M? 57. When 1.0M NaCl is added to a saturated solution of AgCl, a white precipitate forms. Write the equation of the equilibrium involved, and use this equation to explain the above observation. (3 marks)

58. Na 2 SO 4 solution is slowly added to a solution which contains 0.10M Ba +2 and 0.10M Pb +2. Consider that K sp (BaSO 4 ) = 1.1 x 10-10 K sp (PbSO 4 ) = 1.1 x 10-8 Which of the following statements describes the result of the addition of Na 2 SO 4? A. BaSO 4 precipitates first because it is more soluble B. PbSO 4 precipitates first because it is more soluble C. BaSO 4 precipitates first because it has lower solubility D. PbSO 4 precipitates first because it has lower solubility 59. A chemist calculates the trial K sp values for the addition of a strontium ion solution to four beakers, each containing different amounts of sulphate ion. The results are summarized in the table below: Beaker Trial K sp One 2.6 x 10-5 Two 1.2 x 10-7 Three 6.9 x 10-9 Four 3.2 x 10-11 Since the actual K sp value for strontium sulphate is 3.8 x 10-7, a precipitate would form in beaker(s) A. One only B. One and two C. Three and four D. Two, three, and four 60. 1.0 x 10-3 moles Cu +2 and 9.0 x 10-3 moles of OH - are added to 1.0L of H 2 O. Which one of the following is the correct value for trial K sp of Cu(OH) 2? A. 2.0 x 10-8 B. 8.1 x 10-8 C. 3.2 x 10-7 D. 9.0 x 10-6 61. Show by calculation, and then state whether or not a precipitate will form when 200.0mL of 1.4x10-6 M AgNO 3 is added to 300.0mL of 1.2x10-3 M NaCl. 62. A 30.0mL sample of a 1.5x10-4 M Zn(NO 3 ) 2 solution is mixed with a 50.0mL sample of 2.0x10-5 M Ca(OH) 2. Determine whether or not a precipitate will form. The K sp for Zn(OH) 2 is 1.8x10-14. (4 marks) 63. Consider the following equilibrium: Zn 3 (PO 4 ) 2 (s) 3Zn +2 (aq) + 2PO 4-3 (aq) If K 3 PO 4 is added to the equilibrium, the equilibrium A. Shifts left, and the value of K sp decreases B. Shifts right, and the value of K sp increases C. Shifts left, and the value of K sp remains constant D. Remains the same, and the value of K sp remains constant.