Question 1

When does a weak acid buffer best?

Accepted Answer

A)  From one pH unit below its pKa to its pKa. 
B)  From its pKa to one pH unit above its pKa. 
C)  Within one pH unit of its pKa, both above and below. 
D)  Weak acids do not make good buffers at all. 
A)  From one pH unit below its pKa to its pKa. 
B)  From its pKa to one pH unit above its pKa. 
C)  Within one pH unit of its pKa, both above and below. 
D)  Weak acids do not make good buffers at all.

Question 2

Buffering capacity refers to

Accepted Answer

A)  the effectiveness of commercial antacids 
B)  the extent to which a buffer solution can counteract the effect of added acid or base 
C)  the pH of a buffer solution 
D)  the molecular weight of the substance used as a buffer 
A)  the effectiveness of commercial antacids 
B)  the extent to which a buffer solution can counteract the effect of added acid or base 
C)  the pH of a buffer solution 
D)  the molecular weight of the substance used as a buffer

Question 3

The tendency for an atom to attract electrons to itself in a chemical bond is called

Accepted Answer

A)  polarity. 
B)  electronegativity. 
C)  hydrophilicity 
D)  electrophilicity. 
A)  polarity. 
B)  electronegativity. 
C)  hydrophilicity 
D)  electrophilicity.

Question 4

The substance most likely to form a micelle is

Accepted Answer

A)  acetic acid 
B)  sodium palmitate 
C)  methyl alcohol 
D)  acetone 
A)  acetic acid 
B)  sodium palmitate 
C)  methyl alcohol 
D)  acetone

Question 5

​ Which of the following statements is true of dipole-induced dipole interactions?

Accepted Answer

A)  They occur between molecules that are dipoles, with the partial positive side of one molecule attracting the partial negative side of another molecule. 
B)  They involve a permanent dipole inducing a transient dipole in a nonpolar molecule. 
C)  They are the attraction between two molecules, lacking dipoles, bumping into each other and distorting each other's electron cloud. 
D)  They give rise to a London dispersion force between transient-induced dipoles. 
A)  They occur between molecules that are dipoles, with the partial positive side of one molecule attracting the partial negative side of another molecule. 
B)  They involve a permanent dipole inducing a transient dipole in a nonpolar molecule. 
C)  They are the attraction between two molecules, lacking dipoles, bumping into each other and distorting each other's electron cloud. 
D)  They give rise to a London dispersion force between transient-induced dipoles.

Question 6

If a solution has a pH = 9.6, the [H+] is

Accepted Answer

A)  2.5 × 1010 
B)  9.6 M 
C)  2.5 M 
D)  2.5 × 10 − 10 M 
E)  9.6 × 10 − 10 M 
A)  2.5 × 1010 
B)  9.6 M 
C)  2.5 M 
D)  2.5 × 10 − 10 M 
E)  9.6 × 10 − 10 M

Question 7

Hydrogen bonds explain which of the following properties of water?

Accepted Answer

A)  Water is a great solvent for all ionic and polar molecules. 
B)  Water has high melting and boiling points for its small size. 
C)  Ice expands when frozen. 
D)  Both the abnormal melting and freezing points and that ice expands when frozen. 
E)  Hydrogen bonds explain all of these properties. 
A)  Water is a great solvent for all ionic and polar molecules. 
B)  Water has high melting and boiling points for its small size. 
C)  Ice expands when frozen. 
D)  Both the abnormal melting and freezing points and that ice expands when frozen. 
E)  Hydrogen bonds explain all of these properties.

Question 8

For an acid that undergoes this reaction:
HA ↔ H+ + A − 
Ka =

Accepted Answer

A)  [H+][A − ]\[HA] 
B)  [H+][HA]\[A − ] 
C)  [HA][A − ]\[H+] 
D)  [A − ]\[HA][H+] 
E)  [H+]\[HA][A − ] 
A)  [H+][A − ]\[HA] 
B)  [H+][HA]\[A − ] 
C)  [HA][A − ]\[H+] 
D)  [A − ]\[HA][H+] 
E)  [H+]\[HA][A − ]

Question 9

When a carboxylate side-chain of one amino acid in a protein is in close proximity to a charged amino group of another amino acid, we call the resulting interaction a(n)

Accepted Answer

A)  ion - dipole bond 
B)  ionic bond 
C)  van der Waal's bond 
D)  salt bridge 
A)  ion - dipole bond 
B)  ionic bond 
C)  van der Waal's bond 
D)  salt bridge

Question 10

Consider a reaction that produces a significant amount of hydrogen ion and is to be carried out a pH 7. Only two acids are available for making the buffer solution. The pKa values for acids A and B are 6.3 and 7.3, respectively. Which acid would serve as the optimum buffer for this reaction? Or would carrying out the reaction in water simply serve as well?

Accepted Answer

A)  acid A 
B)  acid B 
C)  water 
D)  both acids would be equally effective 
A)  acid A 
B)  acid B 
C)  water 
D)  both acids would be equally effective

Question 11

Ionic compounds and polar covalent compounds tend to dissolve in water because of

Accepted Answer

A)  ion-dipole and dipole-dipole interactions 
B)  dipole-induced dipole interactions 
C)  van der Waals bonds 
D)  hydrophobic interactions 
A)  ion-dipole and dipole-dipole interactions 
B)  dipole-induced dipole interactions 
C)  van der Waals bonds 
D)  hydrophobic interactions

Question 12

Which of the following is not true?

Accepted Answer

A)  A buffer is a solution which maintains a solution at a neutral pH 
B)  Buffer solutions are made to resist change in pH 
C)  Zwitterion buffers are less likely to interfere with biological reactions than non-zwitterions 
D)  HEPES is a zwitterion buffer 
A)  A buffer is a solution which maintains a solution at a neutral pH 
B)  Buffer solutions are made to resist change in pH 
C)  Zwitterion buffers are less likely to interfere with biological reactions than non-zwitterions 
D)  HEPES is a zwitterion buffer

Question 13

Which of the following compounds is most likely to form a micelle?

Accepted Answer

A)  Acetic acid. 
B)  Glucose. 
C)  Glycerol. 
D)  Sodium palmitate. 
E)  Sodium phosphate. 
A)  Acetic acid. 
B)  Glucose. 
C)  Glycerol. 
D)  Sodium palmitate. 
E)  Sodium phosphate.

Question 14

Which of the following properties of water are related to its ability to form hydrogen bonds?

Accepted Answer

A)  boiling point 
B)  melting point 
C)  density 
D)  solvent potency 
E)  all of the choices 
A)  boiling point 
B)  melting point 
C)  density 
D)  solvent potency 
E)  all of the choices

Question 15

A London dispersion force is another name for a(n)

Accepted Answer

A)  induced dipole - induced dipole bond 
B)  ionic bond 
C)  covalent bond 
D)  non-polar bond 
A)  induced dipole - induced dipole bond 
B)  ionic bond 
C)  covalent bond 
D)  non-polar bond

Question 16

An HCl solution has a pH = 3. If you dilute 10 mL of the solution to 1000mL, the final pH will be:

Accepted Answer

A)  1.0 
B)  2.0 
C)  The pH does not change. 
D)  4.0 
E)  5.0 
A)  1.0 
B)  2.0 
C)  The pH does not change. 
D)  4.0 
E)  5.0

Question 17

Which of the following molecules is amphipathic?

Accepted Answer

A)  sodium chloride 
B)  acetic acid 
C)  benzene 
D)  palmitic acid 
A)  sodium chloride 
B)  acetic acid 
C)  benzene 
D)  palmitic acid

Question 18

The dissociation constant for an acid with a pKa value of 6.0 is

Accepted Answer

A)  1 × 10 − 6 
B)  − 1 × 106 
C)  1 × 106 
D)  − 1 × 10 − 6 
A)  1 × 10 − 6 
B)  − 1 × 106 
C)  1 × 106 
D)  − 1 × 10 − 6

Question 19

What is the pH of an acetic acid solution where the concentration of acetic acid is 2 mM and the concentration of sodium acetate is 20 mM. The pKa of acetic acid is 4.76.

Accepted Answer

A)  5.76 
B)  10.6 
C)  12.6 
D)  8.8 
A)  5.76 
B)  10.6 
C)  12.6 
D)  8.8

Question 20

Exhibit 2A The structure of ATP with various groups labeled. Group III is the entire phosphate group.  
Refer to Exhibit 2A. Which of the functional groups is the most electrophilic?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  The answer cannot be determined without further information. 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  The answer cannot be determined without further information.

Exam 2: Water the Solvent for Biochemical Reactions

When does a weak acid buffer best?

Buffering capacity refers to

The tendency for an atom to attract electrons to itself in a chemical bond is called

The substance most likely to form a micelle is

​ Which of the following statements is true of dipole-induced dipole interactions?

If a solution has a pH = 9.6, the [H+] is

Hydrogen bonds explain which of the following properties of water?

For an acid that undergoes this reaction: HA ↔ H+ + A − Ka =

When a carboxylate side-chain of one amino acid in a protein is in close proximity to a charged amino group of another amino acid, we call the resulting interaction a(n)

Ionic compounds and polar covalent compounds tend to dissolve in water because of

Which of the following is not true?

Which of the following compounds is most likely to form a micelle?

Which of the following properties of water are related to its ability to form hydrogen bonds?

A London dispersion force is another name for a(n)

An HCl solution has a pH = 3. If you dilute 10 mL of the solution to 1000mL, the final pH will be:

Which of the following molecules is amphipathic?

The dissociation constant for an acid with a pKa value of 6.0 is

What is the pH of an acetic acid solution where the concentration of acetic acid is 2 mM and the concentration of sodium acetate is 20 mM. The pKa of acetic acid is 4.76.

Exhibit 2A The structure of ATP with various groups labeled. Group III is the entire phosphate group. Refer to Exhibit 2A. Which of the functional groups is the most electrophilic?

Biochemistry and the Organization of Cells

Amino Acids and Peptides

The Three Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins Enzymes

The Behavior of Proteins Enzymes Mechanisms and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids How Structure Conveys Information

Biosynthesis of Nucleic Acids Replication

Transcription of the Genetic Code the Biosynthesis of Rna

Protein Synthesis Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses Cancer and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism Cellular Signaling

Filters

Which of the following statements is true of dipole-induced dipole interactions?

If a solution has a pH = 9.6, the [H⁺] is

For an acid that undergoes this reaction: HA ↔ H⁺ + A⁻ K_a =

The dissociation constant for an acid with a pK_a value of 6.0 is

What is the pH of an acetic acid solution where the concentration of acetic acid is 2 mM and the concentration of sodium acetate is 20 mM. The pK_a of acetic acid is 4.76.