Question 1

All buffer solutions operate at a pH at or near 7.

Accepted Answer

A) True 
 B)False

Question 2

Formic acid (HCO2H)is a weak acid found in the venom of bees and ant stings.Which of the following is an accurate statement concerning an aqueous solution of formic acid? HCO2H(aq)+ H2O(l) ?  H3O+(aq)+ HCO2?(aq) Ka = 1.8 × 10?4

Accepted Answer

A) The reaction between formic acid and water is slow,due to the low value for Ka. 
B) A formic acid solution predominantly contains undissociated HCO2H molecules. 
C) A formic acid solution predominantly contains H3O+ and HCO2? ions. 
D) A formic acid solution contains a greater concentration of dissolved ions than it does neutral formic acid molecules. 
E) A formic acid solution contains equal amounts of H3O+ and HCO2H. 
A) The reaction between formic acid and water is slow,due to the low value for Ka. 
B) A formic acid solution predominantly contains undissociated HCO2H molecules. 
C) A formic acid solution predominantly contains H3O+ and HCO2? ions. 
D) A formic acid solution contains a greater concentration of dissolved ions than it does neutral formic acid molecules. 
E) A formic acid solution contains equal amounts of H3O+ and HCO2H.

Question 3

Consider two beakers,one containing 1.0 M HCl and the other containing 1.0 M CH3COOH.Which solution would have the lowest pH?

Accepted Answer

A) 1.0 M CH3COOH because its solution contains a lower hydronium ion concentration than 1.0 M HCl 
B) 1.0 M HCl because its solution contains a higher hydronium ion concentration than 1.0 M CH3COOH 
C) 1.0 M HCl because its solution contains a lower hydronium ion concentration than 1.0 M CH3COOH 
D) 1.0 M CH3COOH because its solution contains a higher hydronium ion concentration than 1.0 M HCl 
E) Both solutions would have the same pH because they have the same concentration. 
A) 1.0 M CH3COOH because its solution contains a lower hydronium ion concentration than 1.0 M HCl 
B) 1.0 M HCl because its solution contains a higher hydronium ion concentration than 1.0 M CH3COOH 
C) 1.0 M HCl because its solution contains a lower hydronium ion concentration than 1.0 M CH3COOH 
D) 1.0 M CH3COOH because its solution contains a higher hydronium ion concentration than 1.0 M HCl 
E) Both solutions would have the same pH because they have the same concentration.

Question 4

A solution containing a buffer has an initial pH of 8.78.If a student adds 5 drops of NaOH(aq)to this solution,what would be a reasonable pH for the resulting solution?

Accepted Answer

A) 7.00 
B) 8.64 
C) 8.78 
D) 8.89 
E) 12.25 
A) 7.00 
B) 8.64 
C) 8.78 
D) 8.89 
E) 12.25

Question 5

Which of the following correctly describes what is meant by the term neutralization?

Accepted Answer

A) the reaction between hydroxide (OH−)and water to form a base 
B) the reaction between a proton (H+)and water to form a hydronium ion (H3O+) 
C) the reaction between an acid and a base to form a salt and water 
D) the reaction between two molecules of water,one acting as an acid and the other acting as a base 
E) the reaction between an oxidizing agent and a reducing agent 
A) the reaction between hydroxide (OH−)and water to form a base 
B) the reaction between a proton (H+)and water to form a hydronium ion (H3O+) 
C) the reaction between an acid and a base to form a salt and water 
D) the reaction between two molecules of water,one acting as an acid and the other acting as a base 
E) the reaction between an oxidizing agent and a reducing agent

Question 6

A standard solution is a solution whose concentration is accurately known.

Accepted Answer

A) True 
 B)False

Question 7

If the hydronium ion concentration of an aqueous solution at 25°C is 5 × 10−6 M,what is the hydroxide ion concentration?

Accepted Answer

A) 2 × 10−10 M 
B) 2 × 10−9 M 
C) 2 × 10−8 M 
D) 2 × 107 M 
E) 2 × 1019 M 
A) 2 × 10−10 M 
B) 2 × 10−9 M 
C) 2 × 10−8 M 
D) 2 × 107 M 
E) 2 × 1019 M

Question 8

Which of the following best represents the autoionization,or self-ionization,of water?

Accepted Answer

A) H2O(l)? H+(aq)+ OH-(aq) 
B) 2H2O(l) ?  2H2(aq)+ O2(aq) 
C) 2H2O(l) ?  H3O+(aq)+ OH-(aq) 
D) H2O(l)? H2(aq)+ O2-(aq) 
E) H+(aq)+ OH-(aq)? H2O(l) 
A) H2O(l)? H+(aq)+ OH-(aq) 
B) 2H2O(l) ?  2H2(aq)+ O2(aq) 
C) 2H2O(l) ?  H3O+(aq)+ OH-(aq) 
D) H2O(l)? H2(aq)+ O2-(aq) 
E) H+(aq)+ OH-(aq)? H2O(l)

Question 9

What is the hydronium ion concentration of a solution with a pH of 6.0?

Accepted Answer

A) 1 × 106 M 
B) 1 × 10−6 M 
C) 6 × 101 M 
D) 6 × 10−1 M 
E) 6 × 10−14 M 
A) 1 × 106 M 
B) 1 × 10−6 M 
C) 6 × 101 M 
D) 6 × 10−1 M 
E) 6 × 10−14 M

Question 10

Titration of 25.0 mL of an HCl solution of unknown concentration requires 14.8 mL of 0.100 M NaOH.What is the molar concentration of the HCl solution? NaOH(aq)+ HCl(aq)→ NaCl(aq)+ H2O(l)

Accepted Answer

A) 0.592 M 
B) 5.87 M 
C) 0.0592 M 
D) 0.0692 M 
E) 1.25 M 
A) 0.592 M 
B) 5.87 M 
C) 0.0592 M 
D) 0.0692 M 
E) 1.25 M

Question 11

What is the [OH−] of a solution that has a pH = 10.95?

Accepted Answer

A) 1.03 M 
B) 1.1 × 10-11 M 
C) 8.9 × 10-4 M 
D) 3.05 M 
E) 7.4 × 10-5 M 
A) 1.03 M 
B) 1.1 × 10-11 M 
C) 8.9 × 10-4 M 
D) 3.05 M 
E) 7.4 × 10-5 M

Question 12

Consider the following generalized buffer solution equilibrium: BH+(aq)+ H2O(l) ?  H3O+(aq)+ B(aq)
When a small amount of a strong base such as sodium hydroxide is added to the solution,which of the four species shown would experience an increase in concentration? (Hint: Use LeChatelier's principle.)

Accepted Answer

A) BH+ 
B) H2O 
C) H3O+ 
D) B 
E) None of the species would increase in concentration. 
A) BH+ 
B) H2O 
C) H3O+ 
D) B 
E) None of the species would increase in concentration.

Question 13

Choose the best classification of the reaction represented by the following equation: C6H12O6(s)+ 6O2(g)→ 6CO2(g)+ 6H2O(l)

Accepted Answer

A) combustion 
B) acid-base 
C) precipitation 
D) decomposition 
E) combination 
A) combustion 
B) acid-base 
C) precipitation 
D) decomposition 
E) combination

Question 14

A buffer solution is prepared by placing twice the concentration of propanoic acid (C2H5COOH,Ka=1.34 ×10−5)as the concentration of its conjugate base sodium propanoate into a flask.The pH of the resulting buffer solution is best described as which of the following?

Accepted Answer

A) less than 4.87 
B) 4.87 
C) between 4.87 and 9.00 
D) greater than 11.00 
E) Undeterminable; the concentrations of the acid and conjugate base must be given. 
A) less than 4.87 
B) 4.87 
C) between 4.87 and 9.00 
D) greater than 11.00 
E) Undeterminable; the concentrations of the acid and conjugate base must be given.

Question 15

A buffer solution contains acetic acid (HC2H3O2)at a concentration of 0.225 M and sodium acetate (NaC2H3O2)at a concentration of 0.164 M.The value of Ka for acetic acid is 1.75 × 10−5.What is the pH of this buffer solution?

Accepted Answer

A) 0.137 
B) 0.862 
C) 2.40 
D) 4.62 
E) 4.76 
A) 0.137 
B) 0.862 
C) 2.40 
D) 4.62 
E) 4.76

Question 16

Which statement concerning the relative strength of acids is FALSE?

Accepted Answer

A) Strong and weak acids differ in their extent of proton transfer to water. 
B) Strong acids are good proton donors; weak acids are poor proton donors. 
C) A strong acid completely transfers its protons to water; a weak acid only partially transfers its protons to water. 
D) Strong acids produce strong conjugate bases; weak acids produce weak conjugate bases. 
E) A strong acid produces more hydronium ions in water than a weak acid of the same concentration. 
A) Strong and weak acids differ in their extent of proton transfer to water. 
B) Strong acids are good proton donors; weak acids are poor proton donors. 
C) A strong acid completely transfers its protons to water; a weak acid only partially transfers its protons to water. 
D) Strong acids produce strong conjugate bases; weak acids produce weak conjugate bases. 
E) A strong acid produces more hydronium ions in water than a weak acid of the same concentration.

Question 17

The pH of a 12.0 M solution of HCl is 1.1.

Accepted Answer

A) True 
 B)False

Question 18

For the reaction shown below,which of the following is a conjugate acid-base pair? C5H5N(aq)+ H2O(l) ?  C5H5NH+(aq)+ OH?(aq)

Accepted Answer

A) C5H5N,H2O 
B) C5H5N,C5H5NH+ 
C) C5H5NH+,OH? 
D) H2O,OH? 
E) C5H5N,C5H5NH+ and H2O,OH? 
A) C5H5N,H2O 
B) C5H5N,C5H5NH+ 
C) C5H5NH+,OH? 
D) H2O,OH? 
E) C5H5N,C5H5NH+ and H2O,OH?

Question 19

What is always a characteristic of a solution that contains a buffer?

Accepted Answer

A) The solution is neutral and has a pH of 7. 
B) The solution contains a small amount of solute dissolved in a large volume of solvent. 
C) The solution has been diluted by the addition of solvent. 
D) The solution resists large changes in pH when small amounts of acids or bases are added. 
E) The solution maintains a constant pH value; no amount of added acid or base can change the pH. 
A) The solution is neutral and has a pH of 7. 
B) The solution contains a small amount of solute dissolved in a large volume of solvent. 
C) The solution has been diluted by the addition of solvent. 
D) The solution resists large changes in pH when small amounts of acids or bases are added. 
E) The solution maintains a constant pH value; no amount of added acid or base can change the pH.

Question 20

A patient's urine sample gave a reading of pH = 8.2.What is the value of [H3O+] in this solution?

Accepted Answer

A) 6.0 × 10-9 M 
B) 0.91 M 
C) 1.6 × 10-8 M 
D) 1.6 × 108 M 
E) 2.7 × 10-4 M 
A) 6.0 × 10-9 M 
B) 0.91 M 
C) 1.6 × 10-8 M 
D) 1.6 × 108 M 
E) 2.7 × 10-4 M

Exam 8: Acids and Bases

All buffer solutions operate at a pH at or near 7.

Formic acid (HCO2H)is a weak acid found in the venom of bees and ant stings.Which of the following is an accurate statement concerning an aqueous solution of formic acid? HCO2H(aq)+ H2O(l) ? H3O+(aq)+ HCO2?(aq) Ka = 1.8 × 10?4

Consider two beakers,one containing 1.0 M HCl and the other containing 1.0 M CH3COOH.Which solution would have the lowest pH?

A solution containing a buffer has an initial pH of 8.78.If a student adds 5 drops of NaOH(aq)to this solution,what would be a reasonable pH for the resulting solution?

Which of the following correctly describes what is meant by the term neutralization?

A standard solution is a solution whose concentration is accurately known.

If the hydronium ion concentration of an aqueous solution at 25°C is 5 × 10−6 M,what is the hydroxide ion concentration?

Which of the following best represents the autoionization,or self-ionization,of water?

What is the hydronium ion concentration of a solution with a pH of 6.0?

Titration of 25.0 mL of an HCl solution of unknown concentration requires 14.8 mL of 0.100 M NaOH.What is the molar concentration of the HCl solution? NaOH(aq)+ HCl(aq)→ NaCl(aq)+ H2O(l)

What is the [OH−] of a solution that has a pH = 10.95?

Choose the best classification of the reaction represented by the following equation: C6H12O6(s)+ 6O2(g)→ 6CO2(g)+ 6H2O(l)

A buffer solution is prepared by placing twice the concentration of propanoic acid (C2H5COOH,Ka=1.34 ×10−5)as the concentration of its conjugate base sodium propanoate into a flask.The pH of the resulting buffer solution is best described as which of the following?

A buffer solution contains acetic acid (HC2H3O2)at a concentration of 0.225 M and sodium acetate (NaC2H3O2)at a concentration of 0.164 M.The value of Ka for acetic acid is 1.75 × 10−5.What is the pH of this buffer solution?

Which statement concerning the relative strength of acids is FALSE?

The pH of a 12.0 M solution of HCl is 1.1.

For the reaction shown below,which of the following is a conjugate acid-base pair? C5H5N(aq)+ H2O(l) ? C5H5NH+(aq)+ OH?(aq)

What is always a characteristic of a solution that contains a buffer?

A patient's urine sample gave a reading of pH = 8.2.What is the value of [H3O+] in this solution?

Chemistry - Methods and Measurement

The Structure of the Atom and the Periodic Table

Structure and Properties of Ionic and Covalent Compounds

Calculations, chemical Changes, and the Chemical Equation

States of Matter: Gases, liquids, and Solids

Solutions

Energy,rate and Equilibrium

The Nucleus, radioactivity, and Nuclear Medicine

An Introduction to Organic Chemistry

The Unsaturated Hydrocarbons: Alkenes, alkynes, and Aromatics

Alcohols, phenols, thiols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Carboxylic Acid Derivatives

Amines and Amides

Carbohydrates

Lipids and Their Functions in Biochemical Systems

Protein Structure and Function

Enzymes

Introduction to Molecular Genetics

Carbohydrate Metabolism

Aerobic Respiration and Energy Production

Fatty Acid Metabolism

Filters

Formic acid (HCO₂H)is a weak acid found in the venom of bees and ant stings.Which of the following is an accurate statement concerning an aqueous solution of formic acid? HCO₂H(aq)+ H₂O(l) ? H₃O⁺(aq)+ HCO₂^?(aq) K_a = 1.8 × 10^?4

Consider two beakers,one containing 1.0 M HCl and the other containing 1.0 M CH₃COOH.Which solution would have the lowest pH?

If the hydronium ion concentration of an aqueous solution at 25°C is 5 × 10⁻⁶ M,what is the hydroxide ion concentration?

Titration of 25.0 mL of an HCl solution of unknown concentration requires 14.8 mL of 0.100 M NaOH.What is the molar concentration of the HCl solution? NaOH(aq)+ HCl(aq)→ NaCl(aq)+ H₂O(l)

What is the [OH⁻] of a solution that has a pH = 10.95?

Choose the best classification of the reaction represented by the following equation: C₆H₁₂O₆(s)+ 6O₂(g)→ 6CO₂(g)+ 6H₂O(l)

A buffer solution is prepared by placing twice the concentration of propanoic acid (C₂H₅COOH,K_a=1.34 ×10⁻⁵)as the concentration of its conjugate base sodium propanoate into a flask.The pH of the resulting buffer solution is best described as which of the following?

A buffer solution contains acetic acid (HC₂H₃O₂)at a concentration of 0.225 M and sodium acetate (NaC₂H₃O₂)at a concentration of 0.164 M.The value of K_a for acetic acid is 1.75 × 10⁻⁵.What is the pH of this buffer solution?

For the reaction shown below,which of the following is a conjugate acid-base pair? C₅H₅N(aq)+ H₂O(l) ? C₅H₅NH⁺(aq)+ OH^?(aq)

A patient's urine sample gave a reading of pH = 8.2.What is the value of [H₃O+] in this solution?