Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

Calculate the solubility of magnesium sulfate, MgSO4, when placed into a 0.10 M MgCl2 solution. Ksp = 5.9 × 10-3

Accepted Answer

A)  4.2 × 10-2 M 
B)  5.9 × 10-2 M 
C)  7.7 × 10-2 M 
D)  3.5 × 10-5 M 
E)  3.5 × 10-6 M 
A)  4.2 × 10-2 M 
B)  5.9 × 10-2 M 
C)  7.7 × 10-2 M 
D)  3.5 × 10-5 M 
E)  3.5 × 10-6 M

Question 3

Make a clear distinction between buffer range and buffer capacity.

Accepted Answer

Buffer range is the range of pH over whi

Question 4

When a weak acid is titrated with a weak 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 determined by the sizes of Ka and Kb. 
E)  is no longer affected by addition of base. 
A)  is greater than 7.0. 
B)  is equal to 7.0. 
C)  is less than 7.0. 
D)  is determined by the sizes of Ka and Kb. 
E)  is no longer affected by addition of base.

Question 5

The solubility of calcium chromate is 1.56 × 10-3 g/100 mL of solution. What is the Ksp for CaCrO4?

Accepted Answer

A)  2.4 × 10-4 
B)  1.5 × 10-5 
C)  7.6 × 10-6 
D)  1.0 × 10-8 
E)  -8 
A)  2.4 × 10-4 
B)  1.5 × 10-5 
C)  7.6 × 10-6 
D)  1.0 × 10-8 
E)  -8

Question 6

What will be the effect of adding 0.5 mL of 0.1 M NaOH to 100 mL of an acetate buffer in which [CH3COOH] = [CH3COO-] = 0.5 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 7

Which of the following substances has the greatest solubility in water?

Accepted Answer

A)  PbI2, Ksp = 7.9 × 10-9 
B)  BaF2, Ksp = 1.5 × 10-6 
C)  Ca(OH)2, Ksp = 6.5 × 10-6 
D)  Zn(IO3)2, Ksp = 3.9 × 10-6 
E)  Ag2SO4, Ksp = 1.5 × 10-5 
A)  PbI2, Ksp = 7.9 × 10-9 
B)  BaF2, Ksp = 1.5 × 10-6 
C)  Ca(OH)2, Ksp = 6.5 × 10-6 
D)  Zn(IO3)2, Ksp = 3.9 × 10-6 
E)  Ag2SO4, Ksp = 1.5 × 10-5

Question 8

Write the ion product expression for calcium phosphate, Ca3(PO4)2.

Accepted Answer

A)    
B)    
C)    
D)    
E)  None of the above is the correct ion product expression. 
A)    
B)    
C)    
D)    
E)  None of the above is the correct ion product expression.

Question 9

Formic acid is a monoprotic acid with a Ka value of 1.8 × 10-4 at 25°C.
a. Calculate the pH of a 0.200 mol L-1 solution of the acid, making any reasonable approximations.
b. If 0.0050 mol of NaOH is added to 100. mL of the solution in (a), calculate the pH of the resultant buffer.

Accepted Answer

Question 10

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 × 10-3 for CdF2.

Accepted Answer

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 Ksp for cadmium nitrate to make meaningful predictions on this system. 
E)  The presence of NaF will raise the solubility of Cd(NO3)2. 
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 Ksp for cadmium nitrate to make meaningful predictions on this system. 
E)  The presence of NaF will raise the solubility of Cd(NO3)2.

Question 11

A sample of a monoprotic acid (HA) weighing 0.384 g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the molar mass of HA?

Accepted Answer

A)  37.0 g/mol 
B)  81.0 g/mol 
C)  128 g/mol 
D)  20.3 g/mol 
E)  211 g/mol 
A)  37.0 g/mol 
B)  81.0 g/mol 
C)  128 g/mol 
D)  20.3 g/mol 
E)  211 g/mol

Question 12

At the equivalence point in an acid-base titration

Accepted Answer

A)  the [H3O+] equals the Ka of the acid. 
B)  the [H3O+] equals the Ka of the indicator. 
C)  the amounts of acid and base which have been combined are in their stoichiometric ratio. 
D)  the pH is 7.0. 
E)  the pH has reached a maximum. 
A)  the [H3O+] equals the Ka of the acid. 
B)  the [H3O+] equals the Ka of the indicator. 
C)  the amounts of acid and base which have been combined are in their stoichiometric ratio. 
D)  the pH is 7.0. 
E)  the pH has reached a maximum.

Question 13

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?

Accepted Answer

A)  4.9 × 10-2 
B)  1.7 × 10-5 
C)  8.5 × 10-6 
D)  4.2 × 10-6 
E)  -6 
A)  4.9 × 10-2 
B)  1.7 × 10-5 
C)  8.5 × 10-6 
D)  4.2 × 10-6 
E)  -6

Question 14

A formic acid buffer containing 0.50 M HCOOH and 0.50 M HCOONa has a pH of 3.77. What will the pH be after 0.010 mol of NaOH has been added to 100.0 mL of the buffer?

Accepted Answer

A)  3.67 
B)  3.78 
C)  3.81 
D)  3.85 
E)  3.95 
A)  3.67 
B)  3.78 
C)  3.81 
D)  3.85 
E)  3.95

Question 15

The pH of blood is 7.35. It is maintained in part by the buffer system composed of carbonic acid (H2CO3) and the bicarbonate (hydrogen carbonate, HCO3-) ion. What is the ratio of [bicarbonate]/[carbonic acid] at this pH? For carbonic acid, Ka1 = 4.2 × 10-7.

Accepted Answer

A)  [bicarbonate]/[carbonic acid] = 0.11 
B)  [bicarbonate]/[carbonic acid] = 0.38 
C)  [bicarbonate]/[carbonic acid] = 2.65 
D)  [bicarbonate]/[carbonic acid] = 9.4 
E)  None of the above ratios is correct. 
A)  [bicarbonate]/[carbonic acid] = 0.11 
B)  [bicarbonate]/[carbonic acid] = 0.38 
C)  [bicarbonate]/[carbonic acid] = 2.65 
D)  [bicarbonate]/[carbonic acid] = 9.4 
E)  None of the above ratios is correct.

Question 16

Citric acid has an acid dissociation constant of 8.4 × 10-4. It would be most effective for preparation of a buffer with a pH of

Accepted Answer

A)  2. 
B)  3. 
C)  4. 
D)  5. 
E)  6. 
A)  2. 
B)  3. 
C)  4. 
D)  5. 
E)  6.

Question 17

What volume of 0.200 M KOH must be added to 17.5 mL of 0.135 M H3PO4 to reach the third equivalence point?

Accepted Answer

A)  3.94 mL 
B)  11.8 mL 
C)  17.5 mL 
D)  23.6 mL 
E)  35.4 mL 
A)  3.94 mL 
B)  11.8 mL 
C)  17.5 mL 
D)  23.6 mL 
E)  35.4 mL

Question 18

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 × 10-4

Accepted Answer

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

Question 19

Calculate the solubility of silver phosphate, Ag3PO4, in pure water. Ksp = 2.6 × 10-18

Accepted Answer

A)  4.0 × 10-5 M 
B)  1.8 × 10-5 M 
C)  4.0 × 10-6 M 
D)  1.5 × 10-6 M 
E)  -6 M 
A)  4.0 × 10-5 M 
B)  1.8 × 10-5 M 
C)  4.0 × 10-6 M 
D)  1.5 × 10-6 M 
E)  -6 M

Exam 19: Ionic Equilibria in Aqueous Systems

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

Calculate the solubility of magnesium sulfate, MgSO4, when placed into a 0.10 M MgCl2 solution. Ksp = 5.9 × 10-3

Make a clear distinction between buffer range and buffer capacity.

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

The solubility of calcium chromate is 1.56 × 10-3 g/100 mL of solution. What is the Ksp for CaCrO4?

What will be the effect of adding 0.5 mL of 0.1 M NaOH to 100 mL of an acetate buffer in which [CH3COOH] = [CH3COO-] = 0.5 M?

Which of the following substances has the greatest solubility in water?

Write the ion product expression for calcium phosphate, Ca3(PO4)2.

Formic acid is a monoprotic acid with a Ka value of 1.8 × 10-4 at 25°C. a. Calculate the pH of a 0.200 mol L-1 solution of the acid, making any reasonable approximations. b. If 0.0050 mol of NaOH is added to 100. mL of the solution in (a), calculate the pH of the resultant buffer.

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 × 10-3 for CdF2.

A sample of a monoprotic acid (HA) weighing 0.384 g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the molar mass of HA?

At the equivalence point in an acid-base titration

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?

A formic acid buffer containing 0.50 M HCOOH and 0.50 M HCOONa has a pH of 3.77. What will the pH be after 0.010 mol of NaOH has been added to 100.0 mL of the buffer?

The pH of blood is 7.35. It is maintained in part by the buffer system composed of carbonic acid (H2CO3) and the bicarbonate (hydrogen carbonate, HCO3-) ion. What is the ratio of [bicarbonate]/[carbonic acid] at this pH? For carbonic acid, Ka1 = 4.2 × 10-7.

Citric acid has an acid dissociation constant of 8.4 × 10-4. It would be most effective for preparation of a buffer with a pH of

What volume of 0.200 M KOH must be added to 17.5 mL of 0.135 M H3PO4 to reach the third equivalence point?

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 × 10-4

Calculate the solubility of silver phosphate, Ag3PO4, in pure water. Ksp = 2.6 × 10-18

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

For a diprotic acid H₂A, the relationship K_a1 > K_a2 is always true.

Calculate the solubility of magnesium sulfate, MgSO₄, when placed into a 0.10 M MgCl₂solution. K_sp = 5.9 × 10^-3

The solubility of calcium chromate is 1.56 × 10^-3 g/100 mL of solution. What is the K_sp for CaCrO₄?

What will be the effect of adding 0.5 mL of 0.1 M NaOH to 100 mL of an acetate buffer in which [CH₃COOH] = [CH₃COO^-] = 0.5 M?

Write the ion product expression for calcium phosphate, Ca₃(PO₄)₂.

Formic acid is a monoprotic acid with a K_a value of 1.8 × 10^-4 at 25°C. a. Calculate the pH of a 0.200 mol L^-1 solution of the acid, making any reasonable approximations. b. If 0.0050 mol of NaOH is added to 100. mL of the solution in (a), calculate the pH of the resultant buffer.

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? K_sp = 6.44 × 10^-3 for CdF₂.

The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the K_sp of PbCl₂?

The pH of blood is 7.35. It is maintained in part by the buffer system composed of carbonic acid (H₂CO₃) and the bicarbonate (hydrogen carbonate, HCO₃^-) ion. What is the ratio of [bicarbonate]/[carbonic acid] at this pH? For carbonic acid, K_a1 = 4.2 × 10^-7.

Citric acid has an acid dissociation constant of 8.4 × 10^-4. It would be most effective for preparation of a buffer with a pH of

What volume of 0.200 M KOH must be added to 17.5 mL of 0.135 M H₃PO₄to reach the third equivalence point?

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? K_b = 6.5 × 10^-4

Calculate the solubility of silver phosphate, Ag₃PO₄, in pure water. K_sp = 2.6 × 10^-18