Question 1

If the Ka of an acid is 1.38 × 10-7, what is the pKa?

Accepted Answer

A)  6.86 
B)  7.14 
C)  8.68 
D)  10.7 
E)  1.38 
A)  6.86 
B)  7.14 
C)  8.68 
D)  10.7 
E)  1.38

Question 2

Polar molecules cannot easily pass through the cell membrane, but hydrophobic molecules can easily pass through the membrane. The two molecules shown in the diagram both have effects that include raising blood pressure. Comparing two molecules to the right, which statement is TRUE?

Accepted Answer

A)  Ephedrine can more easily pass through the cell membrane than epinephrine. 
B)  Epinephrine can more easily pass through the cell membrane than ephedrine. 
C)  Both epinephrine and ephedrine can pass through the cell membrane equally well. 
D)  Neither epinephrine nor ephedrine can pass through the cell membrane. 
E)  None of the statements is true. 
A)  Ephedrine can more easily pass through the cell membrane than epinephrine. 
B)  Epinephrine can more easily pass through the cell membrane than ephedrine. 
C)  Both epinephrine and ephedrine can pass through the cell membrane equally well. 
D)  Neither epinephrine nor ephedrine can pass through the cell membrane. 
E)  None of the statements is true.

Question 3

According to the titration curve above, acid A has a buffering range of:

Accepted Answer

A)  0.3 M to 0.8 M OH. 
B)  0.9 to 1.0 M OH. 
C)  pH 3.5 to pH 4.2. 
D)  pH 2.8 to pH 3.8. 
E)  pH 2.8 to pH 4.8. 
A)  0.3 M to 0.8 M OH. 
B)  0.9 to 1.0 M OH. 
C)  pH 3.5 to pH 4.2. 
D)  pH 2.8 to pH 3.8. 
E)  pH 2.8 to pH 4.8.

Question 4

The aqueous solution with the HIGHEST pH is:

Accepted Answer

A)  1 M HCl. 
B)  1 M NH3 (pKa = 9.25). 
C)  0.5 M NaHCO3 (pKa = 3.77). 
D)  0.1 M NaOH. 
E)  0.001 M NaOH. 
A)  1 M HCl. 
B)  1 M NH3 (pKa = 9.25). 
C)  0.5 M NaHCO3 (pKa = 3.77). 
D)  0.1 M NaOH. 
E)  0.001 M NaOH.

Question 5

Formic acid is used in the venom of some species of ants. What is the pH of a 0.2 M solution of formic acid (Ka = 1.78 × 10-4 M)?

Accepted Answer

A)  8.90 
B)  4.45 
C)  3.75 
D)  2.2 Ionization of Water, Weak Acids, and Weak Bases2 
E)  1.72 
A)  8.90 
B)  4.45 
C)  3.75 
D)  2.2 Ionization of Water, Weak Acids, and Weak Bases2 
E)  1.72

Question 6

Which compound acts as a diprotic acid?

Accepted Answer

A)  CH3COOH 
B)  NH4+ 
C)  H2CO3 
D)  H3PO4 
E)  CH3CH2OH 
A)  CH3COOH 
B)  NH4+ 
C)  H2CO3 
D)  H3PO4 
E)  CH3CH2OH

Question 7

In proteins, the amino acid histidine (His) plays an important role in many biological reactions. The pKa for the protonation of His to form HisH+ = 6.0. When pH = 7.0, what is the fraction of total histidine that will be in the HisH+ form?

Accepted Answer

To determine the fraction of total histi

Question 8

As two atoms get nearer to each other, do van der Waals attractive forces always increase?

Accepted Answer

As two atoms approach each other, the va

Question 9

The H+ concentration of a solution is 5.6 × 10-5 M. What is the pH?

Accepted Answer

A)  -4.25 
B)  4.25 
C)  5.65 
D)  -9.75 
E)  9.75 
A)  -4.25 
B)  4.25 
C)  5.65 
D)  -9.75 
E)  9.75

Question 10

Which statement regarding long-chain fatty acids in aqueous solution is NOT true?

Accepted Answer

A)  Fatty acids in small concentrations are surrounded by highly ordered water molecules in a "cage-like" structure. 
B)  Fatty acids will cluster together to minimize the lipid surface area. 
C)  Fatty acids will form micelles to sequester hydrophobic groups from water. 
D)  The driving force of solubilizing fatty acids is increasing entropy of the fatty acid. 
E)  All the statements are true. 
A)  Fatty acids in small concentrations are surrounded by highly ordered water molecules in a "cage-like" structure. 
B)  Fatty acids will cluster together to minimize the lipid surface area. 
C)  Fatty acids will form micelles to sequester hydrophobic groups from water. 
D)  The driving force of solubilizing fatty acids is increasing entropy of the fatty acid. 
E)  All the statements are true.

Question 11

Which list correctly shows bond/interaction strength in DECREASING order (strongest to weakest)?

Accepted Answer

A)  covalent bond > hydrogen bond > ionic bond > van der Waals interaction 
B)  covalent bond > ionic bond > hydrogen bond > van der Waals interaction 
C)  ionic bond > covalent bond > hydrogen bond > van der Waals interaction 
D)  covalent bond > van der Waals interaction > ionic bond > hydrogen bond 
E)  hydrogen bond > ionic bond > van der Waals interaction > covalent bond 
A)  covalent bond > hydrogen bond > ionic bond > van der Waals interaction 
B)  covalent bond > ionic bond > hydrogen bond > van der Waals interaction 
C)  ionic bond > covalent bond > hydrogen bond > van der Waals interaction 
D)  covalent bond > van der Waals interaction > ionic bond > hydrogen bond 
E)  hydrogen bond > ionic bond > van der Waals interaction > covalent bond

Question 12

Phosphoric acid (H3PO4) has three dissociable protons, with the pKa's shown below. Which form of phosphoric acid predominates in a solution at pH 4? Explain your answer.
Acid
pKa
H3PO4
2.14
H2PO4-
6.86
HPO42-
12.4

Accepted Answer

At pH 4, the predominant form of phospho

Question 13

Which diagram CORRECTLY illustrates the clustering of lipids in the formation of a micelle?

Accepted Answer

A)  A 
B)  B 
C)  both A and B 
D)  neither A nor B 
A)  A 
B)  B 
C)  both A and B 
D)  neither A nor B

Question 14

According to the Henderson-Hasselbalch equation, when is the pH equal to the pKa?

Accepted Answer

A)  when the concentration of acid is close to zero 
B)  when the pH approaches 7 
C)  when the concentration of the conjugate base is equal to the ionization constant for water 
D)  when the concentration of the conjugate base is equal to the concentration of the acid. 
E)  None of the answers is correct. 
A)  when the concentration of acid is close to zero 
B)  when the pH approaches 7 
C)  when the concentration of the conjugate base is equal to the ionization constant for water 
D)  when the concentration of the conjugate base is equal to the concentration of the acid. 
E)  None of the answers is correct.

Question 15

A TRUE statement about hydrophobic interactions is that they:

Accepted Answer

A)  are the driving force in the formation of micelles of amphipathic compounds in water. 
B)  do not contribute to the structure of water-soluble proteins. 
C)  have bonding energies of approximately 20-40 Kjoule per mole. 
D)  involve the ability of water to denature proteins. 
E)  primarily involve the effect of polar solutes on the entropy of aqueous systems. 
A)  are the driving force in the formation of micelles of amphipathic compounds in water. 
B)  do not contribute to the structure of water-soluble proteins. 
C)  have bonding energies of approximately 20-40 Kjoule per mole. 
D)  involve the ability of water to denature proteins. 
E)  primarily involve the effect of polar solutes on the entropy of aqueous systems.

Question 16

When two atoms are joined together covalently, the van der Waals radius of the atoms in the covalent bond are _____ than the radius of the atoms alone because the joined atoms are _____.

Accepted Answer

A)  shorter; pulled together by the shared electron pair 
B)  shorter; pulled together by the attraction of the nucleus to the bonded atom 
C)  shorter; pulled together by hydrogen bonding 
D)  longer; repelled due to the shared electron pair 
E)  longer; repelled due to the nuclear repulsion between bonded atoms 
A)  shorter; pulled together by the shared electron pair 
B)  shorter; pulled together by the attraction of the nucleus to the bonded atom 
C)  shorter; pulled together by hydrogen bonding 
D)  longer; repelled due to the shared electron pair 
E)  longer; repelled due to the nuclear repulsion between bonded atoms

Question 17

What is the pH of a solution containing 0.2 M acetic acid (pKa = 4.7) and 0.1 M sodium acetate?

Accepted Answer

To determine the pH of a solution contai

Question 18

If ice were denser than water, how would that affect life on earth?

Accepted Answer

If ice were denser than water, it would

Question 19

List the acids in INCREASING order of strength (weakest to strongest): nitrous acid (Ka = 4.0 × 10-4); carbonic acid (Ka = 4.4 × 10-7); acetic acid (Ka = 1.7 × 10-5); phosphoric acid (Ka = 7.3 × 10-3)

Accepted Answer

A)  acetic acid, carbonic acid, nitrous acid, phosphoric acid 
B)  carbonic acid, acetic acid, nitrous acid, phosphoric acid 
C)  acetic acid, nitrous acid, carbonic acid, phosphoric acid 
D)  phosphoric acid, nitrous acid, acetic acid, carbonic acid 
E)  carbonic acid, phosphoric acid, nitrous acid, acetic acid 
A)  acetic acid, carbonic acid, nitrous acid, phosphoric acid 
B)  carbonic acid, acetic acid, nitrous acid, phosphoric acid 
C)  acetic acid, nitrous acid, carbonic acid, phosphoric acid 
D)  phosphoric acid, nitrous acid, acetic acid, carbonic acid 
E)  carbonic acid, phosphoric acid, nitrous acid, acetic acid

Question 20

Carbon dioxide, produced by glucose oxidation, is not very soluble. How does the body transport this molecule through blood to be exhaled from the lungs?

Accepted Answer

A)  CO2 can be directly bound to hemoglobin for transport. 
B)  CO2 can be converted to the more soluble CO for transport. 
C)  CO2 can be converted to the more soluble HCO3-1 for transport. 
D)  CO2 can be bound by erythrocytes for transport. 
E)  CO2 is only produced in the lungs. 
A)  CO2 can be directly bound to hemoglobin for transport. 
B)  CO2 can be converted to the more soluble CO for transport. 
C)  CO2 can be converted to the more soluble HCO3-1 for transport. 
D)  CO2 can be bound by erythrocytes for transport. 
E)  CO2 is only produced in the lungs.

Exam 2: Water

If the Ka of an acid is 1.38 × 10-7, what is the pKa?

Polar molecules cannot easily pass through the cell membrane, but hydrophobic molecules can easily pass through the membrane. The two molecules shown in the diagram both have effects that include raising blood pressure. Comparing two molecules to the right, which statement is TRUE?

According to the titration curve above, acid A has a buffering range of:

The aqueous solution with the HIGHEST pH is:

Formic acid is used in the venom of some species of ants. What is the pH of a 0.2 M solution of formic acid (Ka = 1.78 × 10-4 M)?

Which compound acts as a diprotic acid?

In proteins, the amino acid histidine (His) plays an important role in many biological reactions. The pKa for the protonation of His to form HisH+ = 6.0. When pH = 7.0, what is the fraction of total histidine that will be in the HisH+ form?

As two atoms get nearer to each other, do van der Waals attractive forces always increase?

The H+ concentration of a solution is 5.6 × 10-5 M. What is the pH?

Which statement regarding long-chain fatty acids in aqueous solution is NOT true?

Which list correctly shows bond/interaction strength in DECREASING order (strongest to weakest)?

Phosphoric acid (H3PO4) has three dissociable protons, with the pKa's shown below. Which form of phosphoric acid predominates in a solution at pH 4? Explain your answer. Acid pKa H3PO4 2.14 H2PO4- 6.86 HPO42- 12.4

Which diagram CORRECTLY illustrates the clustering of lipids in the formation of a micelle?

According to the Henderson-Hasselbalch equation, when is the pH equal to the pKa?

A TRUE statement about hydrophobic interactions is that they:

When two atoms are joined together covalently, the van der Waals radius of the atoms in the covalent bond are _____ than the radius of the atoms alone because the joined atoms are _____.

What is the pH of a solution containing 0.2 M acetic acid (pKa = 4.7) and 0.1 M sodium acetate?

If ice were denser than water, how would that affect life on earth?

List the acids in INCREASING order of strength (weakest to strongest): nitrous acid (Ka = 4.0 × 10-4); carbonic acid (Ka = 4.4 × 10-7); acetic acid (Ka = 1.7 × 10-5); phosphoric acid (Ka = 7.3 × 10-3)

Carbon dioxide, produced by glucose oxidation, is not very soluble. How does the body transport this molecule through blood to be exhaled from the lungs?

The Foundations of Biochemistry

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

If the K_a of an acid is 1.38 × 10^-⁷, what is the pK_a?

Formic acid is used in the venom of some species of ants. What is the pH of a 0.2 M solution of formic acid (K_a = 1.78 × 10^-⁴ M)?

In proteins, the amino acid histidine (His) plays an important role in many biological reactions. The pK_a for the protonation of His to form HisH⁺ = 6.0. When pH = 7.0, what is the fraction of total histidine that will be in the HisH⁺ form?

The H⁺ concentration of a solution is 5.6 × 10^-⁵ M. What is the pH?

Phosphoric acid (H₃PO₄) has three dissociable protons, with the pK_a's shown below. Which form of phosphoric acid predominates in a solution at pH 4? Explain your answer. Acid pK_a H₃PO₄ 2.14 H₂PO₄^- 6.86 HPO₄²^- 12.4

According to the Henderson-Hasselbalch equation, when is the pH equal to the pK_a?

When two atoms are joined together covalently, the van der Waals radius of the atoms in the covalent bond are _ than the radius of the atoms alone because the joined atoms are _.

What is the pH of a solution containing 0.2 M acetic acid (pK_a = 4.7) and 0.1 M sodium acetate?

List the acids in INCREASING order of strength (weakest to strongest): nitrous acid (K_a = 4.0 × 10^-⁴); carbonic acid (K_a = 4.4 × 10^-⁷); acetic acid (K_a = 1.7 × 10^-⁵); phosphoric acid (K_a = 7.3 × 10^-³)