6
3U-Solutions -prac-test
Note: this sample test does not reflect length, weight and necessarily every topic and type of question that will be on the unit test. It should not be your only study tool, but rather used in conjunction with class notes, textbook and other resources.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. Which of the following is not an electrolyte?
a. / sugar dissolved in water / d. / a basic solutionb. / salt dissolved in water / e. / Gatorade solution
c. / an acid solution
____ 2. Which of the following mixtures is homogeneous?
a. / orange juice from concentrate / d. / sand and rocksb. / milk / e. / jello
c. / clay in water
____ 3. Which of the following does not dissolve very well in water?
a. / sodium chloride / d. / gasolineb. / sugar / e. / lemon juice
c. / ethanol
____ 4. The separation of ions that occur as ionic compounds dissolve in water is known as
a. / dissociation / d. / dissolvingb. / separation / e. / deportation
c. / protonation
____ 5. The dissociation equation K3PO4(s) ® 3K+(aq) + PO4–3(aq) represents
a. / soluble potassium phosphate / d. / soluble potassium phosphideb. / insoluble sodium phosphate / e. / soluble potassium phosphite
c. / soluble potassium carbonate
____ 6. Water is referred to as the "universal solvent" because
a. / Water molecules are small in size.b. / Water molecules are highly polar.
c. / Water molecules form hydrogen bonds.
d. / a, b, and c only
e. / a and c only
____ 7. Vinegar is labelled with its concentration ratio measured in
a. / mol/L / d. / ppmb. / % by volume / e. / ppb
c. / % by mass
____ 8. Which of the following is a common source of water contamination?
a. / landfill leachateb. / agricultural fertilizers and pesticides
c. / road salt runoff
d. / mining and mine tailings
e. / all of the above
____ 9. The process of rapidly mixing chemicals with water to make small particles in the water clump together is
a. / coagulation / d. / filtrationb. / flocculation / e. / mixing
c. / softening
____ 10. Which of the following is not a disinfectant used in the treatment of water?
a. / O3(g) / d. / KMnO4(aq)b. / ClO2(g) / e. / NH3(aq)
c. / NaF
____ 11. The contamination of Walkerton, Ontario's water supply in 2000 was caused by
a. / lead / d. / E. coli bacteriab. / mercury / e. / nitrates
c. / pesticides
____ 12. A bottle contains 3 L of 12 mol/L H2SO4 solution. After half of the contents are used up, the remaining solution has a concentration of
a. / 18 mol/L / d. / 3 mol/Lb. / 12 mol/L / e. / none of the above
c. / 6 mol/L
____ 13. Water hardness is caused by which of the following ions?
a. / Mn2+ / d. / both b and cb. / Ca2+ / e. / Fe3+
c. / Mg2+
____ 14. A hardness index of 500 ppm indicates that the water is
a. / soft / d. / hardb. / slightly hard / e. / very hard
c. / moderately hard
____ 15. The soda-lime process is a water-softening process involving the chemicals
a. / potassium nitrate and sodium chlorideb. / sodium carbonate and calcium hydroxide
c. / lithium carbonate and barium hydroxide
d. / all of the above
e. / none of the above
____ 16. Which of the following solutions when mixed, would produce a PbI2(s) precipitate?
a. / PbCl2 and AgI / d. / a and b onlyb. / Pb(NO3)2 and KI / e. / b and c only
c. / Pb(C2H3O2)2 and NaI
____ 17. Which of the following processes occur during the tertiary treatment of wastewater?
a. / reverse osmosis / d. / all of the aboveb. / steam distillation / e. / none of the above
c. / chemical precipitation
____ 18. Which of the following cations in solution would precipitate the NO3– ion?
a. / Na+ / d. / Cu2+b. / Ca2+ / e. / none of the above
c. / Fe3+
____ 19. Quantitative analysis of solutions is different from qualitative analysis because quantitative analysis involves
a. / colour changesb. / calculations of C, n, or V for solutions
c. / colourimetry
d. / use of a spectrophotometer
e. / none of the above
____ 20. A company is recycling expensive silver metal from a concentrated silver nitrate solution. Consider the following skeleton equation: AgNO3(aq) + Cu(s) ® Cu(NO3)2(aq) + Ag(s)
What are the coefficients required, in order from left to right, to make this equation balanced?
a. / 2, 1, 1, 2 / d. / 3, 1, 1, 3b. / 1, 2, 2, 1 / e. / equation is already balanced
c. / 2, 2, 2, 2
____ 21. Based on the solubility curve, _____ KNO3/100 mL of water at _____ would be a supersaturated solution.
a. / 30 g , 10ºC / d. / 100 g , 60ºCb. / 50 g , 40ºC / e. / 100 g , 70ºC
c. / 80 g , 50ºC
____ 22. Breathalyzers can determine blood alcohol content indirectly by
a. / aqueous dichromate ions (orange) + alcohol ® chromium(III) ions (green)b. / permanganate ions turning purple
c. / copper solution turning pink
d. / water + alcohol ® red
e. / none of the above
____ 23. Hydrogen chloride gas dissolves in water as follows: HCl(g) ® H+(aq) + Cl–(aq)
This reaction is classified as
a. / dissociation / d. / a and b onlyb. / separation / e. / none of the above
c. / ionization
____ 24. Nitric acid is classified as a strong acid because
a. / it has high electrical conductivityb. / it ionizes about 50%
c. / ionizes more than 99%
d. / both a and c
e. / it has a higher concentration than other acids
____ 25. A dilute solution of a strong acid can be more dangerous than a concentrated solution of a weak acid because
a. / there are still more H+(aq) ions in the dilute strong acidb. / there are more molecules in the strong acid
c. / the amount of H+(aq) ions is the same for both
d. / the strong acid contains chloride ions
e. / the weak acid has fewer molecules than the strong acid
____ 26. pH is an important factor in
a. / consumer products / d. / soil in gardens and farmsb. / swimming pools / e. / all of the above
c. / human blood
____ 27. An acid solution has a pH of 4.0. If water is added to this solution to increase its volume, which of the following will occur?
a. / The pH will decrease. / d. / [H+(aq)] will decrease.b. / The pH will increase. / e. / b and d only
c. / [H+(aq)] will increase.
____ 28. Most antacids have a pH value of
a. / 7.0 / d. / 5.0b. / 8.0 / e. / 4.0
c. / 10.0
____ 29. How much more acidic is vinegar (pH = 2.0) than coffee (pH = 5.0)?
a. / 3.0 / d. / 2.5b. / 1000 / e. / 0.4
c. / 100
____ 30. According to Bronsted-Lowry an acid is
a. / a substance that produces hydronium ionsb. / a substance that produces hydroxide ions
c. / a proton acceptor
d. / a proton donor
e. / really just neutral
Completion
Complete each statement.
31. Sodium chloride and potassium iodide are ______compounds that dissolve in water.
32. ______is the process of decomposing ionic solids into their respective ions.
33. Concentrations of dissolved ions in bottled water are expressed in units of parts per ______.
34. A(n) ______solution is one for which the precise concentration is known.
35. As the temperature of a solution decreases, the ______of most solid solutes decreases.
36. A(n) ______solution is one that cannot dissolve any more solute at the existing temperature.
37. Sodium and potassium are always soluble in precipitation reactions. Since they do not participate, they are called ______ions.
38. Many fertilizers contain nitrate compounds because these compounds are ______in water and can be easily absorbed by plants.
39. The first step in secondary treatment of wastewater involves ______the water to support aerobic bacteria.
40. The point during a titration at which the indicator changes colour is called the ______.
Short Answer
41. Explain the difference between dilute and concentrated solutions.
42. Give an example of a solution with a solid solute dissolved in a solid solvent.
43. List three chemical substances that pollute water.
44. Briefly explain the most important step in water treatment.
45. Explain the approximate concentration criteria that distinguishes dilute and concentrated solutions.
46. Briefly explain how home water softeners work.
47. A chemist mixes aqueous potassium iodide with lead(II) acetate to produce a bright yellow precipitate for her chemistry magic show. Write the net ionic equation for this reaction.
48. Briefly describe two problems that would result from discharging untreated sewage into lakes.
49. State the approximate pH values for the following substances:
(a) vinegar
(b) distilled water
(c) swimming pool water
(d) normal rain
(e) seawater
50. A 0.1 mol/L solution of nitric acid has a pH of about 1 and a 0.1 mol/L solution of acetic acid has a pH of about 3.
(a) Account for this difference in pH.
(b) Explain which acid is more acidic and by how much.
51. List three empirical properties for acids and three empirical properties for bases.
52. Write the balanced chemical equation for the neutralization of aqueous phosphoric acid by potassium hydroxide.
Problem
53. Saline solutions are used in hospitals to replace lost body fluids and electrolyes. A normal saline solution is made by dissolving 0.9 g of NaCl in 100 mL of water. Calculate its concentration as % by mass.
54. The concentration of an HCl acid solution is initially 6.0 mol/L. What would the concentration of a new solution be if 200 mL of the original HCl solution is diluted to 1.0 L with water?
55. Standard solutions of sodium oxalate, Na2C2O4(aq), are required for certain types of chemical analyses. If 8.5 g of sodium oxalate is dissolved in 500 mL of distilled water, calculate the concentration of the sodium ion and the concentration of the oxalate ion dissolved in this solution.
56. Assume that laundry detergent is mostly sodium carbonate. Calculate the concentration of the sodium carbonate if a 95.0-g scoop of detergent is dissolved in 25.0 L of water in the washing machine?
57. A saturated solution of KClO3 is cooled from 50ºC to 5ºC when it is placed into a fridge. Calculate how much potassium chlorate will crystallize from a 1.0-L solution.
58. A student mixed 100.0 mL of a 0.100 mol/L solution of barium chloride with 100.0 mL of a 0.100 mol/L solution of iron(III) sulphate. The barium sulphate precipitate was filtered, dried, and was measured to have a mass of 2.0 g. Calculate the % yield of the barium sulphate.
59. Calculate the pH of vinegar which has a hydrogen ion concentration of 1 ´ 10–2 mol/L.
60. A swimming pool has a pH of 7.5. Calculate the hydrogen ion concentration in the pool.
61. Spinach leaves were boiled and 20.00 mL of the spinach juice was analyzed for its oxalic acid content. The spinach juice was titrated with a 0.50 mol/L calcium chloride solution and 5.25 mL of the calcium chloride was required to produce the calcium oxalate precipitate. Calculate the concentration of the oxalic acid in the spinach juice.
62. Cameco in Port Hope, Ontario uses hydrofluoric acid to make an uranium hexafluoride product which is used a fuel for nuclear reactors. A waste drum containing 85.0 L of 6.0 mol/L hydrofluoric acid needs to be neutralized so that it isn't hazardous. Calculate the mass of potassium hydroxide pellets that would be required to completely neutralize the acid.
63. A commercial rust remover contains 7.30 mol/L of phosphoric acid. Calculate the mass of calcium carbonate scale inside a coffeemaker that can be dissolved by 45.0 mL of this solution.
64. A student has accidentally spilled 100.0 mL of 3.0 mol/L nitric acid onto the lab bench. What mass of sodium bicarbonate would the teacher need to sprinkle on this spill to neutralize and clean it up?
6
Soln's-Prac-Test
Answer Section
MULTIPLE CHOICE
1. ANS: A PTS: 1 REF: K/U OBJ: 6.1
STA: SS2.01
2. ANS: A PTS: 1 REF: K/U OBJ: 6.1
STA: SS2.01
3. ANS: D PTS: 1 REF: K/U OBJ: 6.2
STA: SS1.01
4. ANS: A PTS: 1 REF: I OBJ: 6.2
STA: SS2.01
5. ANS: A PTS: 1 REF: K/U OBJ: 6.2
STA: SS1.02
6. ANS: D PTS: 1 REF: K/U OBJ: 6.2
STA: SS1.01
7. ANS: B PTS: 1 REF: I OBJ: 6.3
STA: SS2.02
8. ANS: E PTS: 1 REF: MC OBJ: 6.4
STA: SS3.03
9. ANS: A PTS: 1 REF: MC OBJ: 6.4
STA: SS3.04
10. ANS: C PTS: 1 REF: MC OBJ: 6.4
STA: SS3.04
11. ANS: D PTS: 1 REF: MC OBJ: 6.4
STA: SS3.03
12. ANS: B PTS: 1 REF: I OBJ: 6.3
STA: SS2.03
13. ANS: D PTS: 1 REF: MC OBJ: 7.2
STA: SS3.05
14. ANS: D PTS: 1 REF: MC OBJ: 7.2
STA: SS3.05
15. ANS: B PTS: 1 REF: MC OBJ: 7.2
STA: SS3.05
16. ANS: E PTS: 1 REF: K/U OBJ: 7.3
STA: SS1.04
17. ANS: D PTS: 1 REF: MC OBJ: 7.4
STA: SS3.04
18. ANS: E PTS: 1 REF: K/U OBJ: 7.5
STA: SS1.04
19. ANS: B PTS: 1 REF: C OBJ: 7.6 | 7.5
STA: SS2.08
20. ANS: A PTS: 1 REF: I OBJ: 7.6
STA: SS2.08
21. ANS: A PTS: 1 REF: I OBJ: 7.1
STA: SS2.04
22. ANS: A PTS: 1 REF: MC OBJ: 7.6
STA: SS3.02
23. ANS: C PTS: 1 REF: C OBJ: 8.1
STA: SS2.07
24. ANS: D PTS: 1 REF: K/U OBJ: 8.1
STA: SS1.06
25. ANS: A PTS: 1 REF: K/U OBJ: 8.1
STA: SS1.06
26. ANS: E PTS: 1 REF: K/U OBJ: 8.2
STA: SS1.07
27. ANS: E PTS: 1 REF: K/U OBJ: 8.2
STA: SS1.07
28. ANS: C PTS: 1 REF: K/U OBJ: 8.2
STA: SS1.07
29. ANS: B PTS: 1 REF: K/U OBJ: 8.2