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Chemistry Ch.16
Question | Answer |
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1) Identify a good buffer. | E) significant amounts of both a weak acid and its conjugate base |
2) Which of the following solutions is a good buffer system? | A) A solution that is 0.10 M HC2H3O2 and 0.10 M LiC2H3O2 |
3) Which of the following solutions is a good buffer system? | B) A solution that is 0.10 M HCN and 0.10 M LiCN |
4) Which one of the following statements is TRUE? | C) A buffer resists pH change by neutralizing added acids and bases. |
5) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.11, which of the following is TRUE? | D) [HCHO2] > [NaCHO2] |
6) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.89, which of the following is TRUE? | A) [HCHO2] < [NaCHO2] |
7) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.74, which of the following is TRUE? | B) [HCHO2] = [NaCHO2] |
10) A buffer solution is 0.100 M in both HC7H5O2 and LiC7H5O2 and has a pH of 4.19. Which of the following pH values would you expect from the addition of a small amount of a dilute solution of a strong base? | D) 4.49 |
28) Which of the following is TRUE? | B) A buffer is most resistant to pH change when [acid] = [conjugate base] |
29) Define buffer capacity. | A) Buffer capacity is the amount of acid or base that can be added to a buffer without destroying its effectiveness. |
30) The highest pH for an effective buffer occurs when the base is how many times as concentrated as the acid? | C) 10 |
31) Which of the following acids (listed with pKa values) and their conjugate base would form a buffer with a pH of 8.10? | C) HClO, pKa = 7.54 |
32) Which of the following acids (listed with Ka values) and their conjugate base would form a buffer with a pH of 2.34? | E) HClO2, Ka = 1.1 x 10-2 |
33) A 1.0 L buffer solution is 0.250 M HC2H3O2 and 0.050 M LiC2H3O2. Which of the following actions will destroy the buffer? | C) adding 0.050 moles of HCl |
34) A 1.0 L buffer solution is 0.050 M HC2H3O2 and 0.250 M LiC2H3O2. Which of the following actions will destroy the buffer? | A) adding 0.050 moles of NaOH |
35) Identify the pH of normal blood. | C) 7.4 |
65) Which of the following compounds will have the highest molar solubility in pure water? | B) MgCO3, Ksp = 6.82 × 10-6 |
66) Which of the following compounds will be more soluble in acidic solution than in pure water? | B) FeS |
67) Identify the salts that are in hard water. | A) CaCO3 and MgCO3 |
68) Which of the following compounds solubility will not be affected by a low pH in solution? | A) AgCl |
79) Which of the following compounds will have the highest molar solubility in pure water? | C) Al(OH)3, Ksp = 3 × 10-34 |
The Ka of hydrazoic acid is 1.9 × 10-5. | D) hydrazoic acid |
The Ka of chloroacetic acid is 1.36 × 10-3. | C) chloroacetate ion |
In which of the following solutions would solid PbBr2 be expected to be the least soluble at 25°C? | C) 0.1 M CaBr2 |
What is the molar solubility of AgCl in 0. 30 M NH3? Ksp for AgCl is 1.8 × 10-10 and Kf for Ag(NH3)2+ is 1.7 × 107. | B) 1.6 × 10- 2 M |
41) What is the molar solubility of AgCl in 0. 10 M NaCN if the colorless complex ion Ag(CN)2- forms? Ksp for AgCl is 1.8 × 10-10 and Kf for Ag(CN)2- is 1.0 × 1021. | A) 0. 050 M |
36) Which of the following is TRUE? | A) The equivalence point is where the amount of acid equals the amount of base during any acid-base titration. |
37) When titrating a strong monoprotic acid and KOH at 25°C, the | D) pH will be equal to 7 at the equivalence point. |
38) When titrating a weak monoprotic acid with NaOH at 25°C, the | C) pH will be greater than 7 at the equivalence point. |
39) When titrating a monoprotic strong acid with a weak base at 25°C, the | E) pH will be less than 7 at the equivalence point. |
40) Identify the most common indicator. | D) phenolphthalein |
41) Identify the indicator that can be used at the lowest pH. | C) crystal violet |
42) Identify the indicator that has two endpoints. | B) thymol blue |
43) Identify the indicator that can be used at the highest pH. | E) alizarin yellow R |
86) Give the equation for an unsaturated solution in comparing Q with Ksp. | B) Q < Ksp |
87) Give the equation for a saturated solution in comparing Q with Ksp. | C) Q = Ksp |
88) Give the equation for a supersaturated solution in comparing Q with Ksp. | A) Q > Ksp |
89) A solution containing AgNO3 is mixed with a solution of NaCl to form a solution that is 0.10 M in AgNO3 and 0.075 M in NaCl. What will happen once these solutions are mixed? Ksp (AgCl) = 1.77 × 10-10. | C) Silver chloride will precipitate out of solution, leaving a saturated AgCl solution. |
90) A solution containing CaCl2 is mixed with a solution of Li2C2O4 to form a solution that is 2.1 × 10-5 M in calcium ion and 4.75 × 10-5 M in oxalate ion. What will happen once these solutions are mixed? Ksp (CaC2O4) = 2.3 × 10-9. | D) Nothing will happen since Ksp > Q for all possible precipitants. |
91) A solution containing CaCl2 is mixed with a solution of Li2C2O4 to form a solution that is 3.5 × 10-4 M in calcium ion and 2.33 × 10-4 M in oxalate ion. What will happen once these solutions are mixed? Ksp (CaC2O4) = 2.3 × 10-9. | D) A precipitate will form since Q > Ksp for calcium oxalate. |
94) Identify the compound that is acid-insoluble. | B) As2S |
95) Identify the compound that is base-insoluble. | C) CoS |
96) A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the precipitate after the addition of 6 M HCl. | C) AgCl |
97) A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the precipitate after the addition of 6 M HCl, then H2S and 0.2 M HCl. | B) CdS |
98) A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the precipitate after the addition of 6 M HCl; H2S and 0.2 M HCl; and OH- to a pH of 8. | E) ZnS |
99) A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the precipitate after the addition of 6 M HCl; H2S and 0.2 M HCl; OH- to a pH of 8; and (NH4)2HPO4 with NH3. | A) Ba3(PO4)2 |
100) A sample contains Ba3(PO4)2, CdS, AgCl, NH4Cl, and ZnS. Identify the soluble ions | D) NH4Cl |
101) A ligand is a molecule or ion that acts as a | D) Lewis base |
102) Describe the solubility of Al(OH)3 with respect to pH. | A) soluble at low pH, insoluble in pH-neutral solution, and soluble at high pH |
103) Gives what happens at low pH for aluminum hydroxide. | A) Al(H2O)63+ dissolves |
104) Gives what happens at neutral pH for aluminum hydroxide. | C) Al(OH)3 precipitates |
105) Gives what happens at high pH for aluminum hydroxide. | B) Al(H2O)2(OH)4- dissolves |
106) A solution contains 2.2 × 10-3 M in Cu2+ and 0.33 M in LiCN. If the Kf for Cu(CN)42- is 1.0 × 1025, how much copper ion remains at equilibrium? | B) 1.9 x 10-26 M |
107) A solution contains 3.8 × 10-2 M in Al3+ and 0.29 M in NaF. If the Kf for AlF63- is 7 × 1019, how much aluminum ion remains at equilibrium? | C) 9.1 × 10-19 M |
37) In which of the following solutions would solid PbBr2 be expected to be the least soluble at 25°C? | C) 0.1 M CaBr2 |
A) 3/4 of the way to second equivalence point of a diprotic acid/strong base titration | 5) pH = pKa2 |
B) equivalence point of a strong acid/strong base titration | 1)pH = 7 |
C) half-way to equivalence point of a weak acid/strong base titration | 2) pH = pKa |
D) equivalence point of a weak base/strong acid titration | 4)pH < 7 |
E) equivalence point of a weak acid/strong base titration | 3)pH > 7 |
40) What is the molar solubility of AgCl in 0. 30 M NH3? Ksp for AgCl is 1.8 × 10-10 and Kf for Ag(NH3)2+ is 1. | B) 1.6 × 10- 2 M7 × 107. |
41) What is the molar solubility of AgCl in 0. 10 M NaCN if the colorless complex ion Ag(CN)2- forms? Ksp for AgCl is 1.8 × 10-10 and Kf for Ag(CN)2- is 1.0 × 1021. | A) 0. 050 M |
42) 0.10 M potassium chromate is slowly added to a solution containing 0. 50 M AgNO3 and 0. 50 M Ba(NO3)2. What is the Ag+ concentration when BaCrO4 just starts to precipitate? The Ksp for Ag2CrO4 and BaCrO4 are 1.1 × 10-12 and 1.2 × 10-10, respectively. | D) 6.8 × 10-2 M |
43) A solution of NaF is added dropwise to a solution that is 0.0144 M in Ba2+. When the concentration of F- exceeds __________ M, BaF2 will precipitate. Neglect volume changes. For BaF2, Ksp = 1.7 × 10-6. | B) 1.1 × 10-2 |