Question 1

Calculate the pH of the following aqueous solutions. Choose your answer from the given pH ranges.
-1.0 M NaHSO4 (pKa for HSO4- = 1.92)

Accepted Answer

A)  pH 9.00-10.99 
B) PH 3.00-5.99 
C) PH 6.00-8.99 
D) PH 11.00-14.00 
E) PH 0.00-2.99 
A)  pH 9.00-10.99 
B) PH 3.00-5.99 
C) PH 6.00-8.99 
D) PH 11.00-14.00 
E) PH 0.00-2.99

Question 2

Calculate [H+] in a 1.0 M solution of Na2CO3 (for H2CO3, Ka1 = 4.3 F1F1F1S1F1F1F10 10-7 and Ka2 = 5.6 F1F1F1S1F1F1F10 10-11).

Accepted Answer

A)  6.6 F1F1F1S1F1F1F10 10-4 M 
B)  7.5 F1F1F1S1F1F1F10 10-13 M 
C)  7.5 F1F1F1S1F1F1F10 10-6 M 
D)  1.3 F1F1F1S1F1F1F10 10-2 M 
E)  none of these 
A)  6.6 F1F1F1S1F1F1F10 10-4 M 
B)  7.5 F1F1F1S1F1F1F10 10-13 M 
C)  7.5 F1F1F1S1F1F1F10 10-6 M 
D)  1.3 F1F1F1S1F1F1F10 10-2 M 
E)  none of these

Question 3

For a neutral solution, it must be true that

Accepted Answer

A)  pH = 7.00. 
B)  [H+] = [OH-]. 
C)  [H2O] = 1 F1F1F1S1F1F1F10 10-14 
D)  [H+] = 0 M. 
E)  At least two of these must be true. 
A)  pH = 7.00. 
B)  [H+] = [OH-]. 
C)  [H2O] = 1 F1F1F1S1F1F1F10 10-14 
D)  [H+] = 0 M. 
E)  At least two of these must be true.

Question 4

The sodium salt, NaA, of a weak acid is dissolved in water; no other substance is added. Which of these statements (to a close approximation) is true?

Accepted Answer

A)  [H+] = [A-] 
B)  [A-] = [OH-] 
C)  [HA] = [OH-] 
D)  [H+] = [OH-] 
E)  none of these 
A)  [H+] = [A-] 
B)  [A-] = [OH-] 
C)  [HA] = [OH-] 
D)  [H+] = [OH-] 
E)  none of these

Question 5

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate Ka for the acid.

Accepted Answer

A)  1.4 F1F1F1S1F1F1F10 10-7 
B)  2.8 F1F1F1S1F1F1F10 10-3 
C)  3.5 F1F1F1S1F1F1F10 10-6 
D)  We need to know the initial concentration of the acid. 
E)  none of these 
A)  1.4 F1F1F1S1F1F1F10 10-7 
B)  2.8 F1F1F1S1F1F1F10 10-3 
C)  3.5 F1F1F1S1F1F1F10 10-6 
D)  We need to know the initial concentration of the acid. 
E)  none of these

Question 6

If Ka for HCN is 6.2 F1F1F1S1F1F1F10 10-10, what is Kb for CN-?

Accepted Answer

A)  6.2 F1F1F1S1F1F1F10 10-24 
B)  6.2 F1F1F1S1F1F1F10 104 
C)  1.6 F1F1F1S1F1F1F10 10-5 
D)  1.6 F1F1F1S1F1F1F10 1023 
E)  none of these 
A)  6.2 F1F1F1S1F1F1F10 10-24 
B)  6.2 F1F1F1S1F1F1F10 104 
C)  1.6 F1F1F1S1F1F1F10 10-5 
D)  1.6 F1F1F1S1F1F1F10 1023 
E)  none of these

Question 7

Which of the following reactions is associated with the definition of Kb?

Accepted Answer

A)  [Al(OH2)6]3+   Al(OH)(OH2)52+ + H+ 
B)  OCl- + H2O   HOCl + OH- 
C)  Al3+ + 6H2O   Al(OH2)63+ 
D)  CN- + H+   HCN 
A)  [Al(OH2)6]3+   Al(OH)(OH2)52+ + H+ 
B)  OCl- + H2O   HOCl + OH- 
C)  Al3+ + 6H2O   Al(OH2)63+ 
D)  CN- + H+   HCN

Question 8

Which reaction does not proceed far to the right?

Accepted Answer

A)  HCN + OH- F1F1F1S1F1F1F10 H2O + CN- 
B)  HCl + H2O F1F1F1S1F1F1F10 H3O+ + Cl- 
C)    
D)  H3O+ + OH- F1F1F1S1F1F1F10 2H2O 
E)    
A)  HCN + OH- F1F1F1S1F1F1F10 H2O + CN- 
B)  HCl + H2O F1F1F1S1F1F1F10 H3O+ + Cl- 
C)    
D)  H3O+ + OH- F1F1F1S1F1F1F10 2H2O 
E)

Question 9

Of the bases NaOH, H2O, CN-, SO42-, and HPO42-, which is the weakest? (Ka for HCN is 6.2 F1F1F1S1F1F1F10 10-10; Ka for HSO4- is 1.2 F1F1F1S1F1F1F10 10-2; and Ka3 for H3PO4, is 4.8 F1F1F1S1F1F1F10 10-13)

Accepted Answer

A)  CN- 
B)  HPO42- 
C)  SO42- 
D)  NaOH 
E)  H2O 
A)  CN- 
B)  HPO42- 
C)  SO42- 
D)  NaOH 
E)  H2O

Question 10

Calculate the pOH of a 0.10 M solution of Ba(OH)2.

Accepted Answer

A)  13.30 
B)  0.70 
C)  13.00 
D)  1.00 
E)  none of these 
A)  13.30 
B)  0.70 
C)  13.00 
D)  1.00 
E)  none of these

Question 11

Calculate the pH of a 0.50 M NH3 (Kb = 1.8 F1F1F1S1F1F1F10 10-5) solution.

Accepted Answer

A)  4.78 
B)  2.52 
C)  7.00 
D)  13.72 
E)  none of these 
A)  4.78 
B)  2.52 
C)  7.00 
D)  13.72 
E)  none of these

Question 12

Calcium carbonate is used in many antacid tablets because it reacts with HCl, the primary acid in the stomach, to produce water, calcium chloride, and carbon dioxide. At 37°C and 760 torr, what volume of CO2 is produced when a person consumes an antacid tablet containing 500.0 mg of CaCO3 to eliminate excess stomach acid? Assume acid is in excess of the carbonate. (R = 0.08206 L.atm/K. mol)

Accepted Answer

A)  17 ml 
B)  30 ml 
C)  1300 ml 
D)  130 ml 
E)  150 ml 
A)  17 ml 
B)  30 ml 
C)  1300 ml 
D)  130 ml 
E)  150 ml

Question 13

If you know Kb for ammonia, NH3, you can calculate the equilibrium constant Ka for the reaction NH4+   NH3 + H+
By which of the following equations?

Accepted Answer

A)  Ka = KwKb 
B)  Ka = 1/Kb 
C)  Ka = Kb/Kw 
D)  Ka = Kw/Kb 
A)  Ka = KwKb 
B)  Ka = 1/Kb 
C)  Ka = Kb/Kw 
D)  Ka = Kw/Kb

Question 14

Calculate the percentage of pyridine (C5H5N) that forms pyridinium ion, C5H5NH+, in a 0.10 M aqueous solution of pyridine (Kb = 1.7 F1F1F1S1F1F1F10 10-9).

Accepted Answer

A)  0.77% 
B)  0.060% 
C)  0.0060% 
D)  1.6% 
E)  0.013% 
A)  0.77% 
B)  0.060% 
C)  0.0060% 
D)  1.6% 
E)  0.013%

Question 15

Calculate the pH of a 2.0 F1F1F1S1F1F1F10 10-8 M solution of HNO3.

Accepted Answer

A)  7.70 
B)  6.96 
C)  7.00 
D)  6.30 
E)  7.04 
A)  7.70 
B)  6.96 
C)  7.00 
D)  6.30 
E)  7.04

Question 16

Calculate the pH of a 1.5 F1F1F1S1F1F1F10 10-7 M solution of HCl.

Accepted Answer

A)  7.18 
B)  7.00 
C)  7.30 
D)  6.82 
E)  6.70 
A)  7.18 
B)  7.00 
C)  7.30 
D)  6.82 
E)  6.70

Question 17

In a solution prepared by dissolving 0.100 mol of propionic acid in enough water to make 1.00 L of solution, the pH is observed to be 1.35. What is Ka for propionic acid (HC3H5O2)?

Accepted Answer

A)  4.5 F1F1F1S1F1F1F10 10-2 
B)  2.0 F1F1F1S1F1F1F10 10-2 
C)  5.0 F1F1F1S1F1F1F10 10-12 
D)  3.6 F1F1F1S1F1F1F10 10-2 
E)  none of these 
A)  4.5 F1F1F1S1F1F1F10 10-2 
B)  2.0 F1F1F1S1F1F1F10 10-2 
C)  5.0 F1F1F1S1F1F1F10 10-12 
D)  3.6 F1F1F1S1F1F1F10 10-2 
E)  none of these

Question 18

Given that the Ka for HOCl is 3.5 F1F1F1S1F1F1F10 10-8, calculate the K value for the reaction of HOCl with OH-.

Accepted Answer

A)  3.5 F1F1F1S1F1F1F10 10-22 
B)  3.5 F1F1F1S1F1F1F10 10-8 
C)  2.9 F1F1F1S1F1F1F10 10-7 
D)  3.5 F1F1F1S1F1F1F10 106 
E)  none of these 
A)  3.5 F1F1F1S1F1F1F10 10-22 
B)  3.5 F1F1F1S1F1F1F10 10-8 
C)  2.9 F1F1F1S1F1F1F10 10-7 
D)  3.5 F1F1F1S1F1F1F10 106 
E)  none of these

Question 19

Which of the following does not represent a conjugate acid-base pair?

Accepted Answer

A)  H3O+ and H2O 
B)  HCN and NH3 
C)  HF and F- 
D)  C5H5NH+ and C5H5N 
E)  none of these 
A)  H3O+ and H2O 
B)  HCN and NH3 
C)  HF and F- 
D)  C5H5NH+ and C5H5N 
E)  none of these

Question 20

You have at your disposal 100.00 mL of 0.650 M HCl and 500.00 mL of 0.300 M NaOH. How many mL of the base have to be added to the full volume of the acid to reach a pH of 1.90?

Accepted Answer

A)  20.4 mL 
B)  43.3 mL 
C)  10.2 mL 
D)  433 mL 
E)  204 mL 
A)  20.4 mL 
B)  43.3 mL 
C)  10.2 mL 
D)  433 mL 
E)  204 mL

Calculate the pH of the following aqueous solutions. Choose your answer from the given pH ranges. -1.0 M NaHSO₄ (pK_a for HSO₄^- = 1.92)

Calculate [H⁺] in a 1.0 M solution of Na₂CO₃ (for H₂CO₃, K_a1 = 4.3  10^-⁷ and K_a2 = 5.6  10^-¹¹).

For a neutral solution, it must be true that

The sodium salt, NaA, of a weak acid is dissolved in water; no other substance is added. Which of these statements (to a close approximation) is true?

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate K_a for the acid.

If K_a for HCN is 6.2  10^-¹⁰, what is K_b for CN^-?

Which of the following reactions is associated with the definition of K_b?

Which reaction does not proceed far to the right?

Of the bases NaOH, H₂O, CN^-, SO₄²^-, and HPO₄²^-, which is the weakest? (K_a for HCN is 6.2  10^-¹⁰; K_a for HSO₄^- is 1.2  10^-²; and K_a3 for H₃PO₄, is 4.8  10^-¹³)

Calculate the pOH of a 0.10 M solution of Ba(OH)₂.

Calculate the pH of a 0.50 M NH₃ (K_b = 1.8  10^-⁵) solution.

If you know K_b for ammonia, NH₃, you can calculate the equilibrium constant K_a for the reaction NH₄⁺ NH₃ + H⁺ By which of the following equations?

Calculate the percentage of pyridine (C₅H₅N) that forms pyridinium ion, C₅H₅NH⁺, in a 0.10 M aqueous solution of pyridine (K_b = 1.7  10^-⁹).

Calculate the pH of a 2.0  10^-⁸ M solution of HNO₃.

Calculate the pH of a 1.5  10^-⁷ M solution of HCl.

In a solution prepared by dissolving 0.100 mol of propionic acid in enough water to make 1.00 L of solution, the pH is observed to be 1.35. What is K_a for propionic acid (HC₃H₅O₂)?

Given that the K_a for HOCl is 3.5  10^-⁸, calculate the K value for the reaction of HOCl with OH^-.

Which of the following does not represent a conjugate acid-base pair?

You have at your disposal 100.00 mL of 0.650 M HCl and 500.00 mL of 0.300 M NaOH. How many mL of the base have to be added to the full volume of the acid to reach a pH of 1.90?

Atoms, Molecules, and Ions

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Chemical Reactions and Solutions Stoichiometry

Gases

Chemical Equilibrium

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

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Exam 7: Acids and Bases

Calculate the pH of the following aqueous solutions. Choose your answer from the given pH ranges. -1.0 M NaHSO4 (pKa for HSO4- = 1.92)

Calculate [H+] in a 1.0 M solution of Na2CO3 (for H2CO3, Ka1 = 4.3  10-7 and Ka2 = 5.6  10-11).

For a neutral solution, it must be true that

The sodium salt, NaA, of a weak acid is dissolved in water; no other substance is added. Which of these statements (to a close approximation) is true?

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate Ka for the acid.

If Ka for HCN is 6.2  10-10, what is Kb for CN-?

Which of the following reactions is associated with the definition of Kb?

Which reaction does not proceed far to the right?

Of the bases NaOH, H2O, CN-, SO42-, and HPO42-, which is the weakest? (Ka for HCN is 6.2  10-10; Ka for HSO4- is 1.2  10-2; and Ka3 for H3PO4, is 4.8  10-13)

Calculate the pOH of a 0.10 M solution of Ba(OH)2.

Calculate the pH of a 0.50 M NH3 (Kb = 1.8  10-5) solution.

If you know Kb for ammonia, NH3, you can calculate the equilibrium constant Ka for the reaction NH4+ NH3 + H+ By which of the following equations?

Calculate the percentage of pyridine (C5H5N) that forms pyridinium ion, C5H5NH+, in a 0.10 M aqueous solution of pyridine (Kb = 1.7  10-9).

Calculate the pH of a 2.0  10-8 M solution of HNO3.

Calculate the pH of a 1.5  10-7 M solution of HCl.

In a solution prepared by dissolving 0.100 mol of propionic acid in enough water to make 1.00 L of solution, the pH is observed to be 1.35. What is Ka for propionic acid (HC3H5O2)?

Given that the Ka for HOCl is 3.5  10-8, calculate the K value for the reaction of HOCl with OH-.

Which of the following does not represent a conjugate acid-base pair?

You have at your disposal 100.00 mL of 0.650 M HCl and 500.00 mL of 0.300 M NaOH. How many mL of the base have to be added to the full volume of the acid to reach a pH of 1.90?

Atoms, Molecules, and Ions

Stoichiometry

Chemical Reactions and Solutions Stoichiometry

Gases

Chemical Equilibrium

Applications of Aqueous Equilibria

Energy, Enthalpy, and Thermochemistry

Spontaneity, Entropy, and Free Energy

Electrochemistry

Quantum Mechanics and Atomic Theory

Bonding: General Concepts

Covalent Bonding: Orbitals

Chemical Kinetics

Liquids and Solids

Properties of Solutions

The Representative Elements

Transition Metals and Coordination Chemistry

The Nucleus: a Chemists View

Organic and Biochemical Molecules

Filters

Calculate the pH of the following aqueous solutions. Choose your answer from the given pH ranges. -1.0 M NaHSO₄ (pK_a for HSO₄^- = 1.92)

Calculate [H⁺] in a 1.0 M solution of Na₂CO₃ (for H₂CO₃, K_a1 = 4.3  10^-⁷ and K_a2 = 5.6  10^-¹¹).

A monoprotic weak acid, when dissolved in water, is 0.92% dissociated and produces a solution with pH = 3.42. Calculate K_a for the acid.

If K_a for HCN is 6.2  10^-¹⁰, what is K_b for CN^-?

Which of the following reactions is associated with the definition of K_b?

Of the bases NaOH, H₂O, CN^-, SO₄²^-, and HPO₄²^-, which is the weakest? (K_a for HCN is 6.2  10^-¹⁰; K_a for HSO₄^- is 1.2  10^-²; and K_a3 for H₃PO₄, is 4.8  10^-¹³)

Calculate the pOH of a 0.10 M solution of Ba(OH)₂.

Calculate the pH of a 0.50 M NH₃ (K_b = 1.8  10^-⁵) solution.

If you know K_b for ammonia, NH₃, you can calculate the equilibrium constant K_a for the reaction NH₄⁺ NH₃ + H⁺ By which of the following equations?

Calculate the percentage of pyridine (C₅H₅N) that forms pyridinium ion, C₅H₅NH⁺, in a 0.10 M aqueous solution of pyridine (K_b = 1.7  10^-⁹).

Calculate the pH of a 2.0  10^-⁸ M solution of HNO₃.

Calculate the pH of a 1.5  10^-⁷ M solution of HCl.

In a solution prepared by dissolving 0.100 mol of propionic acid in enough water to make 1.00 L of solution, the pH is observed to be 1.35. What is K_a for propionic acid (HC₃H₅O₂)?

Given that the K_a for HOCl is 3.5  10^-⁸, calculate the K value for the reaction of HOCl with OH^-.