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A lab technician adds 0.20 mol of NaF to 1.00 L of 0.35 M cadmium nitrate, Cd(NO3) 2. Which of the following statements is correct? Ksp = 6.44 × 103 for CdF2.


A) Cadmium fluoride precipitates until the solution is saturated.
B) The solution is unsaturated and no precipitate forms.
C) The solubility of cadmium fluoride is increased by the presence of additional fluoride ions.
D) One must know K sp for cadmium nitrate to make meaningful predictions on this system.
E) The presence of NaF will raise the solubility of Cd(NO 3) 2.

F) All of the above
G) D) and E)

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If 10.0 g of NaF and 20.0 g of HF are dissolved in water to make one liter of solution, what will the pH be? For HF, Ka = 6.8 × 104.


A) 7.13
B) 2.54
C) 1.57
D) 3.17
E) 4.86

F) B) and C)
G) A) and D)

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Use the following information to calculate the solubility product constant, Ksp, for CuCl. A saturated solution of CuCl in water was prepared and filtered. From the filtrate, 1.0 L was measured out into a beaker and evaporated to dryness. The solid CuCl residue recovered in the beaker was found to weigh 0.041g.


A) K sp = 1.7 × 10 y9
B) K sp = 1.7 × 10 y7
C) K sp = 1.7 × 10 5
D) K sp = 4.3 × 10 4
E) K sp = 2.1 × 10 2

F) C) and D)
G) A) and E)

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A popular buffer solution consists of carbonate (CO32) and hydrogen carbonate (HCO3) conjugate acid-base pair. Which, if any, of the following such buffers has the highest buffer capacity?


A) 0.9 M CO 3 2 and 0.1 M HCO 3
B) 0.1 M CO 3 2 and 0.9 M HCO 3
C) 0.5 M CO 3 2 and 0.5 M HCO 3
D) 0.1 M CO 3 2 and 0.1 M HCO 3
E) They all have the same buffer capacity.

F) A) and E)
G) B) and E)

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For a diprotic acid H2A, the relationship Ka1 > Ka2 is always true.

A) True
B) False

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The solubility of aluminum hydroxide in water __________ when dilute nitric acid is added to it.


A) increases
B) decreases
C) does not change
D) first increases, then decreases
E) first decreases, then increases

F) A) and E)
G) A) and C)

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A 25.0-mL sample of 0.10 M C2H3NH2 (ethylamine) is titrated with 0.15 M HCl. What is the pH of the solution after 9.00 mL of acid have been added to the amine? Kb = 6.5 × 104


A) 11.08
B) 10.88
C) 10.74
D) 10.55
E) 10.49

F) None of the above
G) A) and E)

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A 20.0-mL sample of 0.50 M H2C6H6O6 (ascorbic acid, a diprotic acid) was titrated with 0.50 M NaOH. The following data were gathered during the titration. A 20.0-mL sample of 0.50 M H<sub>2</sub>C<sub>6</sub>H<sub>6</sub>O<sub>6 </sub>(ascorbic acid, a diprotic acid)  was titrated with 0.50 M NaOH. The following data were gathered during the titration.   What is K<sub>a2</sub> for ascorbic acid? A) 6.8 × 10 <sup>−</sup><sup>5</sup> B) 6.2 × 10 <sup>−</sup><sup>6</sup> C) 6.2 × 10 <sup>−</sup><sup>7</sup> D) 6.2 × 10 <sup>−</sup><sup>8</sup> E) 2.8 × 10 <sup>−</sup><sup>12</sup> What is Ka2 for ascorbic acid?


A) 6.8 × 10 5
B) 6.2 × 10 6
C) 6.2 × 10 7
D) 6.2 × 10 8
E) 2.8 × 10 12

F) A) and D)
G) All of the above

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A 20.0-mL sample of 0.30 M HBr is titrated with 0.15 M NaOH. What is the pH of the solution after 40.3 mL of NaOH have been added to the acid?


A) 2.95
B) 3.13
C) 10.87
D) 11.05
E) 13.14

F) B) and D)
G) A) and D)

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What is the pH of a solution that consists of 0.50 M H2C6H6O6 (ascorbic acid) and 0.75 M NaHC6H6O6 (sodium ascorbate) ? For ascorbic acid, Ka = 6.8 × 105


A) 3.76
B) 3.99
C) 4.34
D) 4.57
E) 5.66

F) A) and D)
G) A) and E)

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Write the ion product expression for silver sulfide, Ag2S.


A) Write the ion product expression for silver sulfide, Ag<sub>2</sub>S. A)    B)    C)    D)    E)
B) Write the ion product expression for silver sulfide, Ag<sub>2</sub>S. A)    B)    C)    D)    E)
C) Write the ion product expression for silver sulfide, Ag<sub>2</sub>S. A)    B)    C)    D)    E)
D) Write the ion product expression for silver sulfide, Ag<sub>2</sub>S. A)    B)    C)    D)    E)
E) Write the ion product expression for silver sulfide, Ag<sub>2</sub>S. A)    B)    C)    D)    E)

F) A) and E)
G) A) and D)

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Which of the following has the highest buffer capacity?


A) 0.10 M H 2PO 4 /0.10 M HPO 4 2
B) 0.50 M H 2PO 4 /0.10 M HPO 4 2
C) 0.10 M H 2PO 4 /0.50 M HPO 4 2
D) 0.50 M H 2PO 4 /0.50 M HPO 4 2
E) They all have the same buffer capacity.

F) C) and D)
G) B) and D)

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The salts X(NO3) 2 and Y(NO3) 2 (where X+ and Y+ are metal ions) are dissolved in water to give a solution which is 0.1 M in each of them. Which of the answers gives the concentration of chloride ions will precipitate the most YCl2 without precipitating any XCl2? Given Ksp values: XCl2, 2 × 105 YCl2, 1 × 1010


A) 1 M Cl
B) 0.1 M Cl
C) 0.01 M Cl
D) 0.001 M Cl
E) 0.0001 M Cl

F) A) and B)
G) B) and C)

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A buffer is prepared by adding 300.0 mL of 2.0 M NaOH to 500.0 mL of 2.0 M CH3COOH. What is the pH of this buffer? Ka = 1.8 × 105


A) 4.57
B) 4.52
C) 4.87
D) 4.92
E) 4.97

F) B) and E)
G) All of the above

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Increasing the concentrations of the components of a buffer solution will increase the buffer capacity.

A) True
B) False

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A lab technician adds 0.015 mol of KOH to 1.00 L of 0.0010 M Ca(NO3) 2. Ksp = 6.5 × 106 for Ca(OH) 2) . Which of the following statements is correct?


A) Calcium hydroxide precipitates until the solution is saturated.
B) The solution is unsaturated and no precipitate forms.
C) The concentration of calcium ions is reduced by the addition of the hydroxide ions.
D) One must know K sp for calcium nitrate to make meaningful predictions on this system.
E) The presence of KOH will raise the solubility of Ca(NO 3) 2.

F) B) and E)
G) A) and B)

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A solution is prepared by adding 100 mL of 0.2 M hydrochloric acid to 100 mL of 0.4 M sodium formate. Is this a buffer solution, and if so, what is its pH?


A) It is a buffer, pH > pK a of formic acid.
B) It is a buffer, pH < pK a of formic acid.
C) It is a buffer, pH = pK a of formic acid.
D) It is a buffer, pH = pK b of sodium formate.
E) Since hydrochloric acid is a strong acid, this is not a buffer.

F) B) and D)
G) C) and D)

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A 25.0-mL sample of 1.00 M NH3 is titrated with 0.15 M HCl. What is the pH of the solution after 15.00 mL of acid have been added to the ammonia solution? Kb = 1.8 × 105


A) 10.26
B) 9.30
C) 9.21
D) 8.30
E) 8.21

F) D) and E)
G) B) and E)

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A phosphate buffer (H2PO4/HPO42) has a pH of 8.3. Which of the following changes will cause the pH to increase?


A) Dissolving a small amount of Na 2HPO 4
B) Dissolving a small amount of NaH 2PO 4
C) Adding a small amount of dilute hydrochloric acid
D) Adding a small amount of dilute phosphoric acid
E) Making the buffer more concentrated by removing some water

F) All of the above
G) A) and B)

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When a weak acid is titrated with a strong base, the pH at the equivalence point


A) is greater than 7.0.
B) is equal to 7.0.
C) is less than 7.0.
D) is equal to the p K a of the acid.
E) is equal to 14.0 − p K b, where p K b is that of the base.

F) A) and B)
G) A) and C)

Correct Answer

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