Question 1

If atoms with greatly differing electronegativities form a bond,that bond will be

Accepted Answer

A)  polar. 
B)  nonpolar. 
C)  amphipathic. 
D)  acidic. 
A)  polar. 
B)  nonpolar. 
C)  amphipathic. 
D)  acidic. A

Question 2

The inflection point of the titration curve for a weak monoprotic acid is equal to its pKa

Accepted Answer

A) True 
 B)False  True

Question 3

Exhibit 2B Contains information on the pK's of some common buffers.
  Refer to Exhibit 2B.Which of the following would make the best buffer at pH =10.0?

Accepted Answer

A)  Acetic acid and sodium acetate 
B)  Tris and its acid form 
C)  H2CO3 and NaHCO3 
D)  Na2HPO4 and NaH2PO4 
E)  NaHCO3 and Na2CO3 
A)  Acetic acid and sodium acetate 
B)  Tris and its acid form 
C)  H2CO3 and NaHCO3 
D)  Na2HPO4 and NaH2PO4 
E)  NaHCO3 and Na2CO3 E

Question 4

A buffer solution

Accepted Answer

A)  is used to control the pH of a solution 
B)  contains at least 100 times more of a weak acid than its conjugate base 
C)  contains at least 100 times less of a weak acid than its conjugate base 
D)  always has a pH of 7 
A)  is used to control the pH of a solution 
B)  contains at least 100 times more of a weak acid than its conjugate base 
C)  contains at least 100 times less of a weak acid than its conjugate base 
D)  always has a pH of 7

Question 5

If a solution has a pH = 6,the [H+] is

Accepted Answer

A)  6 M 
B)  106 M 
C)  10-6 M 
D)  0.6 M 
A)  6 M 
B)  106 M 
C)  10-6 M 
D)  0.6 M

Question 6

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 7

Which of the following is true about ionic compounds?

Accepted Answer

A)  They are more likely to dissolve in non-polar solvents than covalent compounds. 
B)  They always dissolve completely in water. 
C)  They never dissolve in polar solvents. 
D)  Some of them dissolve completely in water or other polar solvents, while others do not. 
A)  They are more likely to dissolve in non-polar solvents than covalent compounds. 
B)  They always dissolve completely in water. 
C)  They never dissolve in polar solvents. 
D)  Some of them dissolve completely in water or other polar solvents, while others do not.

Question 8

A buffer solution at pH 10 has a ratio of [HA]/[A-] of 10.What is the pKa of the acid?

Accepted Answer

A)  8 
B)  9 
C)  10 
D)  11 
E)  12 
A)  8 
B)  9 
C)  10 
D)  11 
E)  12

Question 9

Which of the following is true?

Accepted Answer

A)  The pH of a solution where the A- to HA ratio is 1 has a pH = pKa. 
B)  If the pH does not equal the pKa, the solution is not a buffer. 
C)  The best buffer for any experiment will always have a pH equal to the pKa. 
D)  If a buffer has more weak acid than conjugate base, the pH will be higher than the pKa. 
A)  The pH of a solution where the A- to HA ratio is 1 has a pH = pKa. 
B)  If the pH does not equal the pKa, the solution is not a buffer. 
C)  The best buffer for any experiment will always have a pH equal to the pKa. 
D)  If a buffer has more weak acid than conjugate base, the pH will be higher than the pKa.

Question 10

The water molecule is polar because:

Accepted Answer

A)  Electrons are not distributed symmetrically in the molecule. 
B)  The hydrogen atoms are found on one "side" of the molecule. 
C)  Hydrogen is less electronegative than oxygen. 
D)  The hydrogen atoms are found on one "side" of the molecule and hydrogen is less electronegative than oxygen. 
E)  All of these are correct. 
A)  Electrons are not distributed symmetrically in the molecule. 
B)  The hydrogen atoms are found on one "side" of the molecule. 
C)  Hydrogen is less electronegative than oxygen. 
D)  The hydrogen atoms are found on one "side" of the molecule and hydrogen is less electronegative than oxygen. 
E)  All of these are correct.

Question 11

Hydrogen bonds can only form when the hydrogen atom is involved in a polar bond.

Accepted Answer

A) True 
 B)False

Question 12

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 13

The ion product constant for water (Kw) is equal to:

Accepted Answer

A)  1014 
B)  107 
C)  100 
D)  10-7 
E)  10-14 
A)  1014 
B)  107 
C)  100 
D)  10-7 
E)  10-14

Question 14

Which of the following molecules is polar?

Accepted Answer

A)  CCl4 
B)  CH4 
C)  CO2 
D)  NH3 
E)  None of these molecules is polar. 
A)  CCl4 
B)  CH4 
C)  CO2 
D)  NH3 
E)  None of these molecules is polar.

Question 15

In a hydrogen bond

Accepted Answer

A)  three atoms lie in a straight line 
B)  there is stronger bonding than in a covalent bond 
C)  unpaired electrons play no role 
D)  none of the above 
A)  three atoms lie in a straight line 
B)  there is stronger bonding than in a covalent bond 
C)  unpaired electrons play no role 
D)  none of the above

Question 16

If the pH of 1 liter of a 1.0 M carbonate buffer is 7.0,what is actual number of moles of H2CO3 and HCO3-? (pK = 6.37)

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 17

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 18

Exhibit 2B Contains information on the pK's of some common buffers.
  Refer to Exhibit 2B.An ammonium buffer would work well at this pH:

Accepted Answer

A)  5.6 
B)  7.0 
C)  9.0 
D)  11.0 
E)  None of these 
A)  5.6 
B)  7.0 
C)  9.0 
D)  11.0 
E)  None of these

Question 19

What is the maximum number of hydrogen bonds a single water molecule can form?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 20

Molecules which contain both hydrophilic and hydrophobic regions are:

Accepted Answer

A)  Amphipathic 
B)  Detergents 
C)  Able to form micelles 
D)  Both amphipathic and detergents. 
E)  All of these 
A)  Amphipathic 
B)  Detergents 
C)  Able to form micelles 
D)  Both amphipathic and detergents. 
E)  All of these

Exam 2: Water: The Solvent for Biochemical Reactions

If atoms with greatly differing electronegativities form a bond,that bond will be

The inflection point of the titration curve for a weak monoprotic acid is equal to its pKa

Exhibit 2B Contains information on the pK's of some common buffers. Refer to Exhibit 2B.Which of the following would make the best buffer at pH =10.0?

A buffer solution

If a solution has a pH = 6,the [H+] is

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

Which of the following is true about ionic compounds?

A buffer solution at pH 10 has a ratio of [HA]/[A-] of 10.What is the pKa of the acid?

Which of the following is true?

The water molecule is polar because:

Hydrogen bonds can only form when the hydrogen atom is involved in a polar bond.

The substance most likely to form a micelle is

The ion product constant for water (Kw) is equal to:

Which of the following molecules is polar?

In a hydrogen bond

If the pH of 1 liter of a 1.0 M carbonate buffer is 7.0,what is actual number of moles of H2CO3 and HCO3-? (pK = 6.37)

When does a weak acid buffer best?

Exhibit 2B Contains information on the pK's of some common buffers. Refer to Exhibit 2B.An ammonium buffer would work well at this pH:

What is the maximum number of hydrogen bonds a single water molecule can form?

Molecules which contain both hydrophilic and hydrophobic regions are:

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: 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

The inflection point of the titration curve for a weak monoprotic acid is equal to its pK_a

If a solution has a pH = 6,the [H⁺] is

A buffer solution at pH 10 has a ratio of [HA]/[A^-] of 10.What is the pK_a of the acid?

The ion product constant for water (K_w) is equal to:

If the pH of 1 liter of a 1.0 M carbonate buffer is 7.0,what is actual number of moles of H₂CO₃ and HCO₃^-? (pK = 6.37)