Question 1

What volume of 0.500 M H2SO4 is needed to react completely with 20.0 mL of 0.400 M LiOH?

Accepted Answer

A)  4.00 mL 
B)  8.00 mL 
C)  12.5 mL 
D)  16.0 mL 
E)  32.0 mL 
A)  4.00 mL 
B)  8.00 mL 
C)  12.5 mL 
D)  16.0 mL 
E)  32.0 mL B

Question 2

Which of the following has the highest buffer capacity?

Accepted Answer

A)  0.10 M H2PO4-/0.10 M HPO42- 
B)  0.50 M H2PO4-/0.10 M HPO42- 
C)  0.10 M H2PO4-/0.50 M HPO42- 
D)  0.50 M H2PO4-/0.50 M HPO42- 
E)  They all have the same buffer capacity. 
A)  0.10 M H2PO4-/0.10 M HPO42- 
B)  0.50 M H2PO4-/0.10 M HPO42- 
C)  0.10 M H2PO4-/0.50 M HPO42- 
D)  0.50 M H2PO4-/0.50 M HPO42- 
E)  They all have the same buffer capacity. D

Question 3

A solution is prepared by adding 500 mL of 0.3 M NaClO to 500 mL of 0.4 M HClO. What is the pH of this solution?

Accepted Answer

A)  The pH will be greater than the pKa of hypochlorous acid. 
B)  The pH will be less than the pKa of hypochlorous acid. 
C)  The pH will be equal to the pKa of hypochlorous acid. 
D)  The pH will equal the pKb of sodium hypochlorite. 
E)  The pH will be none of the above. 
A)  The pH will be greater than the pKa of hypochlorous acid. 
B)  The pH will be less than the pKa of hypochlorous acid. 
C)  The pH will be equal to the pKa of hypochlorous acid. 
D)  The pH will equal the pKb of sodium hypochlorite. 
E)  The pH will be none of the above. B

Question 4

When 0.300 g of a diprotic acid was titrated with 0.100 M LiOH, 40.0 mL of the LiOH solution was needed to reach the second equivalence point. Identify the formula of the diprotic acid.

Accepted Answer

A)  H2S 
B)  H2C2O4 
C)  H2C4H4O6 
D)  H2Se 
E)  H2Te 
A)  H2S 
B)  H2C2O4 
C)  H2C4H4O6 
D)  H2Se 
E)  H2Te

Question 5

The solubility of magnesium phosphate is 2.27 × 10-3 g/1.0 L of solution. What is the Ksp for Mg3(PO4)2?

Accepted Answer

A)  6.5 × 10-12 
B)  6.0 × 10-14 
C)  5.2 × 10-24 
D)  4.8 × 10-26 
E)  1.0 × 10-26 
A)  6.5 × 10-12 
B)  6.0 × 10-14 
C)  5.2 × 10-24 
D)  4.8 × 10-26 
E)  1.0 × 10-26

Question 6

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

Accepted Answer

A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0. 
D)  is equal to the pKa of the acid. 
E)  is equal to 14.0 - pKb , where pKb is that of the base. 
A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0. 
D)  is equal to the pKa of the acid. 
E)  is equal to 14.0 - pKb , where pKb is that of the base.

Question 7

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

Accepted Answer

A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0, but is not 3.5. 
D)  is equal to the pKa of the acid. 
E)  is equal to 3.5. 
A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0, but is not 3.5. 
D)  is equal to the pKa of the acid. 
E)  is equal to 3.5.

Question 8

An acetate buffer has a pH of 4.40. Which of the following changes will cause the pH to decrease?

Accepted Answer

A)  dissolving a small amount of solid sodium acetate 
B)  adding a small amount of dilute hydrochloric acid 
C)  adding a small amount of dilute sodium hydroxide 
D)  dissolving a small amount of solid sodium chloride 
E)  diluting the buffer solution with water 
A)  dissolving a small amount of solid sodium acetate 
B)  adding a small amount of dilute hydrochloric acid 
C)  adding a small amount of dilute sodium hydroxide 
D)  dissolving a small amount of solid sodium chloride 
E)  diluting the buffer solution with water

Question 9

What will be the effect of adding 0.5 mL of 0.1 M HCl to 100 mL of a phosphate buffer in which [H2PO4-] = [HPO42-] = 0.35 M?

Accepted Answer

A)  The pH will increase slightly. 
B)  The pH will increase significantly. 
C)  The pH will decrease slightly. 
D)  The pH will decrease significantly. 
E)  Since it is a buffer solution, the pH will not be affected. 
A)  The pH will increase slightly. 
B)  The pH will increase significantly. 
C)  The pH will decrease slightly. 
D)  The pH will decrease significantly. 
E)  Since it is a buffer solution, the pH will not be affected.

Question 10

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

Accepted Answer

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

Question 11

Barium sulfate (BaSO4) is a slightly soluble salt, with Ksp = 1.1 × 10-10. What mass of Ba2+ ions will be present in 1.0 L of a saturated solution of barium sulfate?

Accepted Answer

A)  -7 g 
B)  1.0 × 10-5 g 
C)  0.0014 g 
D)  0.0024 g 
E)  > 0.05 g 
A)  -7 g 
B)  1.0 × 10-5 g 
C)  0.0014 g 
D)  0.0024 g 
E)  > 0.05 g

Question 12

Which, if any, of the following aqueous mixtures would be a buffer system?

Accepted Answer

A)  CH3COOH, NaH2PO4 
B)  H2CO3, HCO3- 
C)  H2PO4-, HCO3- 
D)  HSO4-, HSO3- 
E)  None of the above will be a buffer solution. 
A)  CH3COOH, NaH2PO4 
B)  H2CO3, HCO3- 
C)  H2PO4-, HCO3- 
D)  HSO4-, HSO3- 
E)  None of the above will be a buffer solution.

Question 13

Fe(NO3)3 (0.00100 mol) and KSCN (0.200 mol) are added to water to make exactly 1 liter of solution. The red complex ion FeSCN2+ is produced. Calculate the concentrations of Fe3+(aq) and FeSCN2+(aq) at equilibrium, if Kf  of the FeSCN2+ is
8.9 × 102.

Accepted Answer

[Fe³⁺] = 5.6

Question 14

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?

Accepted Answer

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

Question 15

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

Accepted Answer

A) True 
 B)False

Question 16

Write the ion product expression for silver sulfide, Ag2S.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 17

Lead(II) iodide, PbI2, is an ionic compound with a solubility product constant
Ksp of 7.9 × 10-9.Calculate the solubility of this compound in
a. pure water.
b. 0.50 mol L-1 KI solution.

Accepted Answer

a. 1.3 × 1

Question 18

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

Accepted Answer

A)  dissolving a small amount of Na2HPO4 
B)  dissolving a small amount of NaH2PO4 
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 
A)  dissolving a small amount of Na2HPO4 
B)  dissolving a small amount of NaH2PO4 
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

Question 19

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. Using the Ksp values listed below, decide which aqueous reagent, if any, will definitely precipitate X+ before precipitating Y+ from solution. Given Ksp values:
XCl2, 1 × 10-5 YCl2, 1 × 10-10 X(OH)2, 1 × 10-10 Y(OH)2, 1 × 10-5

Accepted Answer

A)  1 M NaCl 
B)  1 M HCl 
C)  1 M HNO3 
D)  1 M NaOH 
E)  None of the above reagents will accomplish the precipitation. 
A)  1 M NaCl 
B)  1 M HCl 
C)  1 M HNO3 
D)  1 M NaOH 
E)  None of the above reagents will accomplish the precipitation.

Question 20

A 35.0-mL sample of 0.20 M LiOH is titrated with 0.25 M HCl. What is the pH of the solution after 23.0 mL of HCl have been added to the base?

Accepted Answer

A)  1.26 
B)  1.67 
C)  12.33 
D)  12.74 
E)  13.03 
A)  1.26 
B)  1.67 
C)  12.33 
D)  12.74 
E)  13.03

Exam 19: Ionic Equilibria in Aqueous Systems

What volume of 0.500 M H2SO4 is needed to react completely with 20.0 mL of 0.400 M LiOH?

Which of the following has the highest buffer capacity?

A solution is prepared by adding 500 mL of 0.3 M NaClO to 500 mL of 0.4 M HClO. What is the pH of this solution?

When 0.300 g of a diprotic acid was titrated with 0.100 M LiOH, 40.0 mL of the LiOH solution was needed to reach the second equivalence point. Identify the formula of the diprotic acid.

The solubility of magnesium phosphate is 2.27 × 10-3 g/1.0 L of solution. What is the Ksp for Mg3(PO4)2?

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

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

An acetate buffer has a pH of 4.40. Which of the following changes will cause the pH to decrease?

What will be the effect of adding 0.5 mL of 0.1 M HCl to 100 mL of a phosphate buffer in which [H2PO4-] = [HPO42-] = 0.35 M?

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

Barium sulfate (BaSO4) is a slightly soluble salt, with Ksp = 1.1 × 10-10. What mass of Ba2+ ions will be present in 1.0 L of a saturated solution of barium sulfate?

Which, if any, of the following aqueous mixtures would be a buffer system?

Fe(NO3)3 (0.00100 mol) and KSCN (0.200 mol) are added to water to make exactly 1 liter of solution. The red complex ion FeSCN2+ is produced. Calculate the concentrations of Fe3+(aq) and FeSCN2+(aq) at equilibrium, if Kf of the FeSCN2+ is 8.9 × 102.

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?

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

Write the ion product expression for silver sulfide, Ag2S.

Lead(II) iodide, PbI2, is an ionic compound with a solubility product constant Ksp of 7.9 × 10-9.Calculate the solubility of this compound in a. pure water. b. 0.50 mol L-1 KI solution.

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

A 35.0-mL sample of 0.20 M LiOH is titrated with 0.25 M HCl. What is the pH of the solution after 23.0 mL of HCl have been added to the base?

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

The Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main Group Elements: Bonding, Structure, and Reactivity

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

What volume of 0.500 M H₂SO₄is needed to react completely with 20.0 mL of 0.400 M LiOH?

The solubility of magnesium phosphate is 2.27 × 10^-3g/1.0 L of solution. What is the K_sp for Mg₃(PO₄)₂?

What will be the effect of adding 0.5 mL of 0.1 M HCl to 100 mL of a phosphate buffer in which [H₂PO₄^-] = [HPO₄^2-] = 0.35 M?

Barium sulfate (BaSO₄) is a slightly soluble salt, with K_sp = 1.1 × 10^-10. What mass of Ba²⁺ ions will be present in 1.0 L of a saturated solution of barium sulfate?

Fe(NO₃)₃ (0.00100 mol) and KSCN (0.200 mol) are added to water to make exactly 1 liter of solution. The red complex ion FeSCN²⁺ is produced. Calculate the concentrations of Fe³⁺(aq) and FeSCN²⁺(aq) at equilibrium, if K_f of the FeSCN²⁺ is 8.9 × 10².

Write the ion product expression for silver sulfide, Ag₂S.

Lead(II) iodide, PbI₂, is an ionic compound with a solubility product constant K_sp of 7.9 × 10^-9.Calculate the solubility of this compound in a. pure water. b. 0.50 mol L^-1 KI solution.

A phosphate buffer (H₂PO₄^-/HPO₄^2-) has a pH of 8.3. Which of the following changes will cause the pH to increase?