Question 1

Calculate the molar solubility of CaF2 in a 0.25 M solution of NaF(aq).(Ksp (CaF2)= 4.0 x 10-11)

Accepted Answer

A) 4.0 x 10-11 M 
B) 6.4 x 10-10 M 
C) 1.6 x 10-10 M 
D) 1.3 x 10-5 M 
E) 2.2 x 10-4 M 
A) 4.0 x 10-11 M 
B) 6.4 x 10-10 M 
C) 1.6 x 10-10 M 
D) 1.3 x 10-5 M 
E) 2.2 x 10-4 M

Question 2

You have 500.0 mL of a buffer solution containing 0.30 M acetic acid (CH3COOH)and 0.20 M sodium acetate (CH3COONa).What will the pH of this solution be after the addition of 20.0 mL of 1.00 M NaOH solution? [Ka = 1.8 × 10-5]

Accepted Answer

A) 4.65 
B) 4.71 
C) 4.56 
D) 4.84 
E) 5.07 
A) 4.65 
B) 4.71 
C) 4.56 
D) 4.84 
E) 5.07

Question 3

The solubility of strontium carbonate is 0.0011 g/100 mL at 20ºC.Calculate the Ksp value for this compound.

Accepted Answer

A) 7.5 × 10-5 
B) 1.5 × 10-4 
C) 5.6 × 10-9 
D) 7.5 × 10-6 
E) 1.5 × 10-3 
A) 7.5 × 10-5 
B) 1.5 × 10-4 
C) 5.6 × 10-9 
D) 7.5 × 10-6 
E) 1.5 × 10-3

Question 4

At 25 °C, the base ionization constant for NH3 is 1.8 × 10-5.Determine the percentage ionization of a 0.150 M solution of ammonia at 25 °C.

Accepted Answer

Question 5

Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer solution with an optimum pH of 9.2-9.3?

Accepted Answer

A) CH3COONa / CH3COOH (Ka = 1.8 × 10-5) 
B) NH3 / NH4Cl (Ka = 5.6 × 10-10) 
C) NaOCl / HOCl (Ka = 3.2 × 10-8) 
D) NaNO2 / HNO2 (Ka = 4.5 × 10-4) 
E) NaCl / HCl 
A) CH3COONa / CH3COOH (Ka = 1.8 × 10-5) 
B) NH3 / NH4Cl (Ka = 5.6 × 10-10) 
C) NaOCl / HOCl (Ka = 3.2 × 10-8) 
D) NaNO2 / HNO2 (Ka = 4.5 × 10-4) 
E) NaCl / HCl

Question 6

Acid dissociation constants for phosphoric acid are given below.   A buffer with a pH = 7.4 can best be made by using

Accepted Answer

A) H3PO4 and NaH2PO4. 
B) NaH2PO4 and Na2HPO4. 
C) Na2HPO4 and Na3PO4. 
D) only NaH2PO4. 
E) only Na2HPO4. 
A) H3PO4 and NaH2PO4. 
B) NaH2PO4 and Na2HPO4. 
C) Na2HPO4 and Na3PO4. 
D) only NaH2PO4. 
E) only Na2HPO4.

Question 7

Will a precipitate form (yes or no)when 50.0 mL of 1.2 × 10-3 M Pb(NO3)2 are added to 50.0 mL of 2.0 × 10-4 M Na2S? If so, identify the precipitate.

Accepted Answer

A) Yes, the precipitate is PbS. 
B) Yes, the precipitate is NaNO3. 
C) Yes, the precipitate is Na2S. 
D) Yes, the precipitate is Pb(NO3)2. 
E) No, a precipitate will not form. 
A) Yes, the precipitate is PbS. 
B) Yes, the precipitate is NaNO3. 
C) Yes, the precipitate is Na2S. 
D) Yes, the precipitate is Pb(NO3)2. 
E) No, a precipitate will not form.

Question 8

Calculate the molar solubility of AgCl in a 0.15 M solution of NH3(aq). (Ksp (AgCl)= 1.6 x 10-10; Kf (Ag(NH3)2+)= 1.5 x 107)

Accepted Answer

A) 6.7 x 10-3 M 
B) 1.3 x 10-5 M 
C) 3.9 x 103 M 
D) 7.5 x 10-2 M 
E) 3.3 x 10-5 M 
A) 6.7 x 10-3 M 
B) 1.3 x 10-5 M 
C) 3.9 x 103 M 
D) 7.5 x 10-2 M 
E) 3.3 x 10-5 M

Question 9

The solubility product for barium sulfate is 1.1 × 10-10.Calculate the molar solubility of barium sulfate.

Accepted Answer

A) 5.5 × 10-11 mol/L 
B) 1.1 × 10-5 mol/L 
C) 2.1 × 10-5 mol/L 
D) 1.1 × 10-10 mol/L 
E) 2.2 × 10-10 mol/L 
A) 5.5 × 10-11 mol/L 
B) 1.1 × 10-5 mol/L 
C) 2.1 × 10-5 mol/L 
D) 1.1 × 10-10 mol/L 
E) 2.2 × 10-10 mol/L

Question 10

Write a net ionic equation for the reaction that occurs when a small amount of hydrochloric acid is added to a buffer solution containing NH4Cl and NH3.

Accepted Answer

Question 11

Write an equation showing the net reaction that occurs when a strong acid is added to a CO32-/HCO3- buffer solution (for carbonic acid, Ka1 = 4.2 × 10-7, Ka2 = 2.4 × 10-8):

Accepted Answer

CO₃^2- + H⁺ @#LAT-DLM& HC

Question 12

Calculate the pH at the equivalence point for the titration of 0.20 M HCl with 0.20 M NH3 (Kb = 1.8 × 10-5).

Accepted Answer

A) 2.87 
B) 4.98 
C) 5.12 
D) 7.00 
E) 11.12 
A) 2.87 
B) 4.98 
C) 5.12 
D) 7.00 
E) 11.12

Question 13

What mass of ammonium nitrate must be added to 350.mL of a 0.150 M solution of ammonia to give a buffer having a pH of 9.00? (Kb(NH3)= 1.8 × 10-5)

Accepted Answer

A) 7.6 g 
B) 2.4 g 
C) 5.4 g 
D) 11 g 
E) 3.3 g 
A) 7.6 g 
B) 2.4 g 
C) 5.4 g 
D) 11 g 
E) 3.3 g

Question 14

What volume of 0.0500 M sodium hydroxide should be added to 250.mL of 0.100 M HCOOH to obtain a solution with a pH of 4.50? [Ka(HCOOH)= 1.7 × 10-4]

Accepted Answer

A) 540 mL 
B) 420 mL 
C) 80.mL 
D) 340 mL 
E) 500.mL 
A) 540 mL 
B) 420 mL 
C) 80.mL 
D) 340 mL 
E) 500.mL

Question 15

Which of the following yields a buffer solution when equal volumes of the two solutions are mixed?

Accepted Answer

A) 0.10M HCl and 0.10 M NaCl 
B) 0.15 M HNO3 and 0.15 M NaNO3 
C) 0.10M HF and 0.10M NaF 
D) 0.10M HClO4 and 0.10 NaClO4 
E) 0.15M HBr and 0.15M NaBr 
A) 0.10M HCl and 0.10 M NaCl 
B) 0.15 M HNO3 and 0.15 M NaNO3 
C) 0.10M HF and 0.10M NaF 
D) 0.10M HClO4 and 0.10 NaClO4 
E) 0.15M HBr and 0.15M NaBr

Question 16

Write a net ionic equation for the reaction occurring when a small amount of sodium hydroxide is added to a NaNO2/HNO2 buffer.

Accepted Answer

Question 17

Calculate the pH of a solution that is 0.15 M CH3COOH and 0.75 M CH3COONa.

Accepted Answer

Question 18

Will a precipitate of magnesium fluoride form when 200.mL of 1.9 × 10-3 M MgCl2 are added to 300.mL of 1.4 × 10-2 M NaF? [Ksp (MgF2)= 6.9 × 10-9]

Accepted Answer

A) Yes, Q > Ksp 
B) No, Q sp 
C) No, Q = Ksp 
D) Yes, Q sp 
E) Yes, Q = Ksp 
A) Yes, Q > Ksp 
B) No, Q sp 
C) No, Q = Ksp 
D) Yes, Q sp 
E) Yes, Q = Ksp

Question 19

Which one of the following combinations cannot function as a buffer solution?

Accepted Answer

A) HCN and KCN 
B) NH3 and (NH4)2SO4 
C) HNO3 and NaNO3 
D) HF and NaF 
E) HNO2 and NaNO2 
A) HCN and KCN 
B) NH3 and (NH4)2SO4 
C) HNO3 and NaNO3 
D) HF and NaF 
E) HNO2 and NaNO2

Question 20

Which one of the following is a buffer solution?

Accepted Answer

A) 0.40 M HCN and 0.10 KCN 
B) 0.20 M CH3COOH 
C) 1.0 M HNO3 and 1.0 M NaNO3 
D) 0.10 M KCN 
E) 0.50 M HCl and 0.10 NaCl 
A) 0.40 M HCN and 0.10 KCN 
B) 0.20 M CH3COOH 
C) 1.0 M HNO3 and 1.0 M NaNO3 
D) 0.10 M KCN 
E) 0.50 M HCl and 0.10 NaCl

Exam 16: Acid-Base Equilibria and Solubility Equilibria

Calculate the molar solubility of CaF2 in a 0.25 M solution of NaF(aq).(Ksp (CaF2)= 4.0 x 10-11)

You have 500.0 mL of a buffer solution containing 0.30 M acetic acid (CH3COOH)and 0.20 M sodium acetate (CH3COONa).What will the pH of this solution be after the addition of 20.0 mL of 1.00 M NaOH solution? [Ka = 1.8 × 10-5]

The solubility of strontium carbonate is 0.0011 g/100 mL at 20ºC.Calculate the Ksp value for this compound.

At 25 °C, the base ionization constant for NH3 is 1.8 × 10-5.Determine the percentage ionization of a 0.150 M solution of ammonia at 25 °C.

Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer solution with an optimum pH of 9.2-9.3?

Acid dissociation constants for phosphoric acid are given below. A buffer with a pH = 7.4 can best be made by using

Will a precipitate form (yes or no)when 50.0 mL of 1.2 × 10-3 M Pb(NO3)2 are added to 50.0 mL of 2.0 × 10-4 M Na2S? If so, identify the precipitate.

Calculate the molar solubility of AgCl in a 0.15 M solution of NH3(aq). (Ksp (AgCl)= 1.6 x 10-10; Kf (Ag(NH3)2+)= 1.5 x 107)

The solubility product for barium sulfate is 1.1 × 10-10.Calculate the molar solubility of barium sulfate.

Write a net ionic equation for the reaction that occurs when a small amount of hydrochloric acid is added to a buffer solution containing NH4Cl and NH3.

Write an equation showing the net reaction that occurs when a strong acid is added to a CO32-/HCO3- buffer solution (for carbonic acid, Ka1 = 4.2 × 10-7, Ka2 = 2.4 × 10-8):

Calculate the pH at the equivalence point for the titration of 0.20 M HCl with 0.20 M NH3 (Kb = 1.8 × 10-5).

What mass of ammonium nitrate must be added to 350.mL of a 0.150 M solution of ammonia to give a buffer having a pH of 9.00? (Kb(NH3)= 1.8 × 10-5)

What volume of 0.0500 M sodium hydroxide should be added to 250.mL of 0.100 M HCOOH to obtain a solution with a pH of 4.50? [Ka(HCOOH)= 1.7 × 10-4]

Which of the following yields a buffer solution when equal volumes of the two solutions are mixed?

Write a net ionic equation for the reaction occurring when a small amount of sodium hydroxide is added to a NaNO2/HNO2 buffer.

Calculate the pH of a solution that is 0.15 M CH3COOH and 0.75 M CH3COONa.

Will a precipitate of magnesium fluoride form when 200.mL of 1.9 × 10-3 M MgCl2 are added to 300.mL of 1.4 × 10-2 M NaF? [Ksp (MgF2)= 6.9 × 10-9]

Which one of the following combinations cannot function as a buffer solution?

Which one of the following is a buffer solution?

Chemistry: the Study of Change

Atoms, Molecules, and Ions

Mass Relationships in Chemical Reactions

Reactions in Aqueous Solutions

Gases

Thermochemistry

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Entropy Free Energy and Equilibrium

Electrochemistry

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Chemistry in the Atmosphere

Metallurgy and the Chemistry of Metals

Nonmetallic Elements and Their Compounds

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Filters

Calculate the molar solubility of CaF₂in a 0.25 M solution of NaF(aq).(K_sp (CaF₂)= 4.0 x 10^-11)

You have 500.0 mL of a buffer solution containing 0.30 M acetic acid (CH₃COOH)and 0.20 M sodium acetate (CH₃COONa).What will the pH of this solution be after the addition of 20.0 mL of 1.00 M NaOH solution? [K_a = 1.8 × 10^-5]

The solubility of strontium carbonate is 0.0011 g/100 mL at 20ºC.Calculate the K_sp value for this compound.

At 25 °C, the base ionization constant for NH₃ is 1.8 × 10^-5.Determine the percentage ionization of a 0.150 M solution of ammonia at 25 °C.

Will a precipitate form (yes or no)when 50.0 mL of 1.2 × 10^-3 M Pb(NO₃)₂ are added to 50.0 mL of 2.0 × 10^-4 M Na₂S? If so, identify the precipitate.

Calculate the molar solubility of AgCl in a 0.15 M solution of NH₃(aq). (K_sp (AgCl)= 1.6 x 10^-10; K_f (Ag(NH₃)₂⁺)= 1.5 x 10⁷)

The solubility product for barium sulfate is 1.1 × 10^-10.Calculate the molar solubility of barium sulfate.

Write a net ionic equation for the reaction that occurs when a small amount of hydrochloric acid is added to a buffer solution containing NH₄Cl and NH₃.

Write an equation showing the net reaction that occurs when a strong acid is added to a CO₃^2-/HCO₃^- buffer solution (for carbonic acid, K_a1 = 4.2 × 10^-7, K_a2 = 2.4 × 10^-8):

Calculate the pH at the equivalence point for the titration of 0.20 M HCl with 0.20 M NH₃ (K_b = 1.8 × 10^-5).

What mass of ammonium nitrate must be added to 350.mL of a 0.150 M solution of ammonia to give a buffer having a pH of 9.00? (K_b(NH₃)= 1.8 × 10^-5)

What volume of 0.0500 M sodium hydroxide should be added to 250.mL of 0.100 M HCOOH to obtain a solution with a pH of 4.50? [K_a(HCOOH)= 1.7 × 10^-4]

Write a net ionic equation for the reaction occurring when a small amount of sodium hydroxide is added to a NaNO₂/HNO₂ buffer.

Calculate the pH of a solution that is 0.15 M CH₃COOH and 0.75 M CH₃COONa.

Will a precipitate of magnesium fluoride form when 200.mL of 1.9 × 10^-3 M MgCl₂ are added to 300.mL of 1.4 × 10^-2 M NaF? [K_sp (MgF₂)= 6.9 × 10^-9]