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 |
1 |  |  A buffer is prepared by dissolving 4.00 g benzoic acid (C6H5COOH, Ka = 6.3 x
10-5) and 4.00 g sodium benzoate (C6H5COONa) in enough water to prepare 1.00 L of solution. Calculate the pH of this buffer.
|
|  | A) | 4.13
|
|  | B) | 4.20
|
|  | C) | 4.27
|
|  | D) | 4.40
|
|  | E) | 5.05
|
 |
 |
2 |  |  Calculate the [NH3]/[NH4+] ratio in an ammonia-ammonium chloride buffer with a pH of 9.00. (Kb for NH3 = 1.8 x
10-5)
|
|  | A) | 0.56/1.00
|
|  | B) | 0.74/1.00
|
|  | C) | 0.86/1.00
|
|  | D) | 1.12/1.00
|
|  | E) | 1.30/1.00
|
 |
 |
3 |  |  A buffer is prepared by adding 0.30 mol CH3COONa to 2.0 L of a 0.10 M CH3COOH solution. Calculate the pH after 0.030 mol HCl are added to the buffer.
(Ka for CH3COOH = 1.8 x
10-5)
|
|  | A) | 1.52
|
|  | B) | 3.57
|
|  | C) | 4.81
|
|  | D) | 5.13
|
|  | E) | 6.34
|
 |
 |
4 |  |  What is the pH of a buffer prepared by adding 180 mL of 0.100 M NaOH to 200 mL of 0.100 M acetic acid? (Ka for CH3COOH = 1.8 x
10-5)
|
|  | A) | 3.79
|
|  | B) | 4.34
|
|  | C) | 4.74
|
|  | D) | 5.04
|
|  | E) | 5.70
|
 |
 |
5 |  |  Consider the titration of 50.00 mL of 0.1000 M HBr with 0.1000 M KOH. Calculate the pH after 49.00 mL of the base has been added to the 50.00 mL of HBr.
|
|  | A) | 2.0
|
|  | B) | 3.0
|
|  | C) | 4.0
|
|  | D) | 6.0
|
|  | E) | 7.0
|
 |
 |
6 |  |  Calculate the pH at the equivalence point for the titration of 0.20 M aniline (C6H5NH2) with 0.20 M HCl. (Kb for aniline = 3.8 x
10-10)
|
|  | A) | 2.6
|
|  | B) | 2.8
|
|  | C) | 5.2
|
|  | D) | 9.4
|
|  | E) | 11.1
|
 |
 |
7 |  |  Citric acid, H3C6H5O7, is a triprotic acid, with Ka1 = 7.5 x
10-4, Ka2 = 1.7 x
10-5, and Ka3 = 4.0 x
10-7. 1.00 x
10-3 mol of aqueous citric acid is titrated with 0.100 M NaOH. Predict the pH of the titration mixture after the addition of 15.0 mL of the NaOH solution.
|
|  | A) | 2.68
|
|  | B) | 3.12
|
|  | C) | 3.95
|
|  | D) | 4.77
|
|  | E) | 6.40
|
 |
 |
8 |  |  An aqueous solution of a weak acid, HA, is titrated with NaOH solution. The pH at the midpoint of the buffer region is 4.5. What is the Ka of the acid?
|
|  | A) | 3.2 x
10-5 |
|  | B) | 3.2 x
10-10 |
|  | C) | 1.8 x
10-3 |
|  | D) | 7.0 x
10-7
|
|  | E) | 4.5
|
 |
 |
9 |  |  Which of the following best describes the acid/base properties of normal rainwater, in the absence of any man-made pollutants?
|
|  | A) | very acidic
|
|  | B) | slightly acidic
|
|  | C) | neutral
|
|  | D) | slightly basic
|
|  | E) | may be basic or acidic
|
 |
 |
10 |  |  Given that the solubility of Ag2CrO4 is 0.0287 g/L, what is the value of its Ksp?
|
|  | A) | Ksp = 3.9 x
10-17 |
|  | B) | Ksp = 6.5 x
10-13 |
|  | C) | Ksp = 8.7 x
10-5 |
|  | D) | Ksp = 7.5 x
10-9 |
|  | E) | Ksp = 2.6 x
10-12
|
 |
 |
11 |  |  The solubility of AlF3 is 6.7 g AlF3 per liter of solution. What is the value of the solubility product constant for AlF3?
|
|  | A) | 1.9 x
10-2 |
|  | B) | 6.0 x
10-3 |
|  | C) | 1.1 x
10-3 |
|  | D) | 4.0 x
10-4
|
|  | E) | 4.1 x
10-5
|
 |
 |
12 |  |  How many grams of AgCl will dissolve in 1.0 L of water? (Ksp for AgCl = 1.7 x
10-10)
|
|  | A) | 1.2 x
10-12 g
|
|  | B) | 2.4 x
10-8 g
|
|  | C) | 4.5 x
10-5 g
|
|  | D) | 1.8 x
10-3 g
|
|  | E) | 1.4 x
10-2 g
|
 |
 |
13 |  |  Calculate the pH of a solution necessary to just begin the precipitation of Mg(OH)2 when [Mg2+] = 0.001 M. (Ksp for Mg(OH)2 = 1.2 x
10-11)
|
|  | A) | 11
|
|  | B) | 10
|
|  | C) | 9
|
|  | D) | 8
|
|  | E) | 4
|
 |
 |
14 |  |  In qualitative analysis, the metals of Ion Group 1 can be separated from other ions by precipitating them as chloride salts. A solution initially contains Ag+ and Pb2+ at a concentration of 0.10 M. Aqueous HCl is added to this solution until the Cl- concentration is 0.10 M. What will the concentrations of Ag+ and Pb2+ be at equilibrium?
(Ksp for AgCl = 1.8 x
10-10; Ksp for PbCl2 = 1.7 x
10-5)
|
|  | A) | [Ag+] = 1.8 x
10-11 M; [Pb2+] = 1.7 x
10-6 M |
|  | B) | [Ag+] = 1.8 x
10-7 M; [Pb2+] = 1.7 x
10-4 M |
|  | C) | [Ag+] = 1.8 x
10-11 M; [Pb2+] = 8.5 x
10-5 M |
|  | D) | [Ag+] = 1.8 x
10-9 M; [Pb2+] = 1.7 x
10-3 M |
|  | E) | [Ag+] = 1.8 x
10-9 M; [Pb2+] = 8.5 x
10-6 M
|
 |
 |
15 |  |  Silver chloride is relatively insoluble in water (Ksp for AgCl = 1.8 x
10-10) but it is soluble in aqueous ammonia, due to the formation of the complex ion Ag(NH3)2+. How many moles of AgCl will dissolve in 1.00 L of solution containing 6.0 moles of free NH3? (Kf for Ag(NH3)2+ = 1.7 x
107)
|
|  | A) | 9.1 x
10-6 mol
|
|  | B) | 2.9 x
10-4 mol
|
|  | C) | 0.0091 mol
|
|  | D) | 0.084 mol
|
|  | E) | 0.33 mol
|
 |