Question 1

Which one of these statements about strong acids is true?

Accepted Answer

A) All strong acids have H atoms bonded to electronegative oxygen atoms. 
B) Strong acids are 100% ionized in water. 
C) The conjugate base of a strong acid is itself a strong base. 
D) Strong acids are very concentrated acids. 
E) Strong acids produce solutions with a higher pH than weak acids. 
A) All strong acids have H atoms bonded to electronegative oxygen atoms. 
B) Strong acids are 100% ionized in water. 
C) The conjugate base of a strong acid is itself a strong base. 
D) Strong acids are very concentrated acids. 
E) Strong acids produce solutions with a higher pH than weak acids.

Question 2

HCN is classified as a weak acid in water. What does this classification mean?

Accepted Answer

A relatively small f

Question 3

Calculate the pH of a carbonated beverage in which the hydrogen ion concentration is 3.4 * 10-4 M.

Accepted Answer

A) 2.34 
B) 3.47 
C) 6.01 
D) 7.99 
E) 10.53 
A) 2.34 
B) 3.47 
C) 6.01 
D) 7.99 
E) 10.53

Question 4

What mass of ammonium chloride must be added to 250. mL of water to give a solution with pH = 4.85? [Kb(NH3)= 1.8 * 10-5]

Accepted Answer

A) 4.7 g 
B) 75 g 
C) 2.3 * 10-3 g 
D) 19 g 
E) 10. g 
A) 4.7 g 
B) 75 g 
C) 2.3 * 10-3 g 
D) 19 g 
E) 10. g

Question 5

Calculate the pH of a 0.021 M NaCN solution. [Ka(HCN)= 4.9 * 10-10]

Accepted Answer

A) 1.68 
B) 3.18 
C) 5.49 
D) 7.00 
E) 10.82 
A) 1.68 
B) 3.18 
C) 5.49 
D) 7.00 
E) 10.82

Question 6

Which solution will have the lowest pH?

Accepted Answer

A) 0.10 M HCN 
B) 0.10 M HNO3 
C) 0.10 M NaCl 
D) 0.10 M H2CO3 
E) 0.10 M NaOH 
A) 0.10 M HCN 
B) 0.10 M HNO3 
C) 0.10 M NaCl 
D) 0.10 M H2CO3 
E) 0.10 M NaOH

Question 7

Which of these species will act as a Lewis acid?

Accepted Answer

A) NH3 
B) NH4+ 
C) H2O 
D) BF3 
E) F- 
A) NH3 
B) NH4+ 
C) H2O 
D) BF3 
E) F-

Question 8

The pH of tomato juice is about 4.5. Calculate the concentration of hydrogen ions in this juice.

Accepted Answer

A) 3. * 10-10 M 
B) 3. * 10-5 M 
C) 5. * 10-4 M 
D) 4. M 
E) 3. * 1010 M 
A) 3. * 10-10 M 
B) 3. * 10-5 M 
C) 5. * 10-4 M 
D) 4. M 
E) 3. * 1010 M

Question 9

Which one of these net ionic equations represents the reaction of a strong acid with a weak base?

Accepted Answer

A) H+(aq)+ OH-(aq)$\rarr$ H2O(aq) 
B) H+(aq)+ CH3NH2(aq)$\rarr$CH3NH3+(aq) 
C) OH-(aq)+ HCN(aq)$\rarr$H2O(aq)+ CN-(aq) 
D) HCN(aq)+ CH3NH2(aq)$\rarr$CH3NH3+  (aq)+ CN-(aq) 
A) H+(aq)+ OH-(aq)$\rarr$ H2O(aq) 
B) H+(aq)+ CH3NH2(aq)$\rarr$CH3NH3+(aq) 
C) OH-(aq)+ HCN(aq)$\rarr$H2O(aq)+ CN-(aq) 
D) HCN(aq)+ CH3NH2(aq)$\rarr$CH3NH3+  (aq)+ CN-(aq)

Question 10

Calculate the pH of a 0.10 M HCN solution that is 0.0070% ionized.

Accepted Answer

A) 1.00 
B) 0.00070 
C) 3.15 
D) 5.15 
E) 7.00 
A) 1.00 
B) 0.00070 
C) 3.15 
D) 5.15 
E) 7.00

Question 11

Due to a highway accident, 150 L of concentrated hydrochloric acid (12.0 M)is released into a lake containing 5.0 * 105 m3 of water. If the pH of this lake was 7.0 prior to the accident, what is the pH of the lake following the accident?

Accepted Answer

A) 5.44 
B) 8.56 
C) 8.44 
D) 5.56 
E) 2.44 
A) 5.44 
B) 8.56 
C) 8.44 
D) 5.56 
E) 2.44

Question 12

What mass of sodium nitrite must be added to 350. mL of water to give a solution with pH = 8.40? [Ka(HNO2)= 5.6 * 10-4]

Accepted Answer

A) 68 g 
B) 1.7 * 10-4 g 
C) 0.039 g 
D) 8.3 g 
E) 24 g 
A) 68 g 
B) 1.7 * 10-4 g 
C) 0.039 g 
D) 8.3 g 
E) 24 g

Question 13

Which one of these salts will form an acidic solution upon dissolving in water?

Accepted Answer

A) LiBr 
B) NaF 
C) NH4Br 
D) KOH 
E) NaCN 
A) LiBr 
B) NaF 
C) NH4Br 
D) KOH 
E) NaCN

Question 14

Aspartic acid (C4H7NO4), one of the 20 essential amino acids, has two ionizable hydrogens. At 25°C, Ka1 = 1.38 * 10-4 and Ka2 = 1.51 * 10-10. What is the concentration of doubly ionized aspartate ions in a 0.125 M aqueous solution of aspartic acid?

Accepted Answer

A) 3.33 * 10-2 M 
B) 4.16 * 10-3 M 
C) 4.15 * 10-3 M 
D) 1.51 * 10-10 M 
E) 2.08 * 10-14 M 
A) 3.33 * 10-2 M 
B) 4.16 * 10-3 M 
C) 4.15 * 10-3 M 
D) 1.51 * 10-10 M 
E) 2.08 * 10-14 M

Question 15

What is the pH of a 0.001 M Ca(OH)2 solution?

Accepted Answer

A) 3.0 
B) 11.0 
C) 2.7 
D) 17.0 
E) 11.3 
A) 3.0 
B) 11.0 
C) 2.7 
D) 17.0 
E) 11.3

Question 16

For H3PO4, Ka1 = 7.3 * 10-3, Ka2 = 6.2 * 10-6, and Ka3 = 4.8 * 10-13. An aqueous solution of NaH2PO4 therefore would be

Accepted Answer

A) neutral. 
B) basic. 
C) acidic. 
A) neutral. 
B) basic. 
C) acidic.

Question 17

Will a 0.1 M solution of NH4CN(aq)be acidic, basic, or neutral?

Accepted Answer

Question 18

What is the pH of a 0.20 M solution of NH4Cl? [Kb(NH3)= 1.8 * 10-5]

Accepted Answer

A) 3.74 
B) 4.98 
C) 6.53 
D) 9.02 
E) 10.25 
A) 3.74 
B) 4.98 
C) 6.53 
D) 9.02 
E) 10.25

Question 19

The equilibrium constant for the reaction C6H5COOH(aq)+ CH3COO-(aq)$\rarr$0 C6H5COO-(aq)+ CH3COOH(aq)
Is 3.6 at 25°C. If Ka for CH3COOH is 1.8 * 10-5, what is the acid dissociation constant for C6H5COOH?

Accepted Answer

A) 5.0 * 10-6 
B) 6.5 * 10-5 
C) 2.3 * 10-4 
D) 8.3 * 10-5 
E) 5.6 * 10-6 
A) 5.0 * 10-6 
B) 6.5 * 10-5 
C) 2.3 * 10-4 
D) 8.3 * 10-5 
E) 5.6 * 10-6

Question 20

Calculate the concentration of chromate ion (CrO42-)in a 0.450 M solution of chromic acid (H2CrO4). [For chromic acid, Ka1 = 0.18, Ka2 = 3.2 * 10-7.]

Accepted Answer

A) 3.2 * 10-7 M 
B) 1.5 * 10-6 M 
C) 0.081 M 
D) 1.1 * 10-6 M 
E) 0.21 M 
A) 3.2 * 10-7 M 
B) 1.5 * 10-6 M 
C) 0.081 M 
D) 1.1 * 10-6 M 
E) 0.21 M

Exam 16: Acids and Bases

Which one of these statements about strong acids is true?

HCN is classified as a weak acid in water. What does this classification mean?

Calculate the pH of a carbonated beverage in which the hydrogen ion concentration is 3.4 * 10-4 M.

What mass of ammonium chloride must be added to 250. mL of water to give a solution with pH = 4.85? [Kb(NH3)= 1.8 * 10-5]

Calculate the pH of a 0.021 M NaCN solution. [Ka(HCN)= 4.9 * 10-10]

Which solution will have the lowest pH?

Which of these species will act as a Lewis acid?

The pH of tomato juice is about 4.5. Calculate the concentration of hydrogen ions in this juice.

Which one of these net ionic equations represents the reaction of a strong acid with a weak base?

Calculate the pH of a 0.10 M HCN solution that is 0.0070% ionized.

Due to a highway accident, 150 L of concentrated hydrochloric acid (12.0 M)is released into a lake containing 5.0 * 105 m3 of water. If the pH of this lake was 7.0 prior to the accident, what is the pH of the lake following the accident?

What mass of sodium nitrite must be added to 350. mL of water to give a solution with pH = 8.40? [Ka(HNO2)= 5.6 * 10-4]

Which one of these salts will form an acidic solution upon dissolving in water?

Aspartic acid (C4H7NO4), one of the 20 essential amino acids, has two ionizable hydrogens. At 25°C, Ka1 = 1.38 * 10-4 and Ka2 = 1.51 * 10-10. What is the concentration of doubly ionized aspartate ions in a 0.125 M aqueous solution of aspartic acid?

What is the pH of a 0.001 M Ca(OH)2 solution?

For H3PO4, Ka1 = 7.3 * 10-3, Ka2 = 6.2 * 10-6, and Ka3 = 4.8 * 10-13. An aqueous solution of NaH2PO4 therefore would be

Will a 0.1 M solution of NH4CN(aq)be acidic, basic, or neutral?

What is the pH of a 0.20 M solution of NH4Cl? [Kb(NH3)= 1.8 * 10-5]

The equilibrium constant for the reaction C6H5COOH(aq)+ CH3COO-(aq) →\rarr→ 0 C6H5COO-(aq)+ CH3COOH(aq) Is 3.6 at 25°C. If Ka for CH3COOH is 1.8 * 10-5, what is the acid dissociation constant for C6H5COOH?

Calculate the concentration of chromate ion (CrO42-)in a 0.450 M solution of chromic acid (H2CrO4). [For chromic acid, Ka1 = 0.18, Ka2 = 3.2 * 10-7.]

Introduction

Atoms, Molecules, and Ions

Stoichiometry

Reactions in Aqueous Solution

Gases

Energy Relationships in Chemical Reactions

The Electronic Structure of Atoms

The Periodic Table

Chemical Bonding I: the Covalent Bond

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Introduction to Organic Chemistry

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria and Solubility Equilibria

Thermodynamics

Redox Reactions and Electrochemistry

The Chemistry of Coordination Compounds

Nuclear Chemistry

Organic Polymerssynthetic and Natural

Filters

Calculate the pH of a carbonated beverage in which the hydrogen ion concentration is 3.4 * 10^-4 M.

What mass of ammonium chloride must be added to 250. mL of water to give a solution with pH = 4.85? [K_b(NH₃)= 1.8 * 10^-5]

Calculate the pH of a 0.021 M NaCN solution. [K_a(HCN)= 4.9 * 10^-10]

Due to a highway accident, 150 L of concentrated hydrochloric acid (12.0 M)is released into a lake containing 5.0 * 10⁵ m³ of water. If the pH of this lake was 7.0 prior to the accident, what is the pH of the lake following the accident?

What mass of sodium nitrite must be added to 350. mL of water to give a solution with pH = 8.40? [K_a(HNO₂)= 5.6 * 10^-4]

Aspartic acid (C₄H₇NO₄), one of the 20 essential amino acids, has two ionizable hydrogens. At 25°C, K_a1 = 1.38 * 10^-4 and K_a2 = 1.51 * 10^-10. What is the concentration of doubly ionized aspartate ions in a 0.125 M aqueous solution of aspartic acid?

What is the pH of a 0.001 M Ca(OH)₂ solution?

For H₃PO₄, K_a1 = 7.3 * 10^-3, K_a2 = 6.2 * 10^-6, and K_a3 = 4.8 * 10^-13. An aqueous solution of NaH₂PO₄ therefore would be

Will a 0.1 M solution of NH₄CN(aq)be acidic, basic, or neutral?

What is the pH of a 0.20 M solution of NH₄Cl? [K_b(NH₃)= 1.8 * 10^-5]

The equilibrium constant for the reaction C₆H₅COOH(aq)+ CH₃COO^-(aq) $\rarr$ 0 C₆H₅COO^-(aq)+ CH₃COOH(aq) Is 3.6 at 25°C. If K_a for CH₃COOH is 1.8 * 10^-5, what is the acid dissociation constant for C₆H₅COOH?

Calculate the concentration of chromate ion (CrO₄^2-)in a 0.450 M solution of chromic acid (H₂CrO₄). [For chromic acid, K_a1 = 0.18, K_a2 = 3.2 * 10^-7.]