Question 1

A titration curve for a weak acid is shown.Which point shows the most buffering?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 2

Since the pKa of acetic acid is 4.8,it can be used to prepare a buffer to maintain physiological pH.

Accepted Answer

A) True 
 B)False

Question 3

Proteins dissolved in water can be hydrolyzed by nucleophilic attack from the water molecules.

Accepted Answer

A) True 
 B)False

Question 4

A solution containing 10-⁸ M HCl and 10-⁸ M acetic acid contains H+ which is supplied mostly by

Accepted Answer

A) the strong acid. 
B) the weak acid. 
C) both the strong and the weak acids. 
D) water. 
E) All of the above. 
A) the strong acid. 
B) the weak acid. 
C) both the strong and the weak acids. 
D) water. 
E) All of the above.

Question 5

Which would you expect to be most soluble in water?

Accepted Answer

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

Question 6

In the detergent sodium dodecyl sulfate,the sulfate groups are very hydrophobic.

Accepted Answer

A) True 
 B)False

Question 7

Which substance do you expect to be most soluble in water?

Accepted Answer

A) Ammonia,NH₃. 
B) Methane,CH₄. 
C) Carbon dioxide,CO2. 
D) Nitrogen,N₂. 
A) Ammonia,NH₃. 
B) Methane,CH₄. 
C) Carbon dioxide,CO2. 
D) Nitrogen,N₂.

Question 8

Which statement best characterizes the distribution of charge in the hydronium ion,H₃O+?

Accepted Answer

A) The positive charge is distributed over all of the atoms in the ion. 
B) The positive charge is localized only on the oxygen atom. 
C) The positive charge is distributed between the three hydrogen atoms only. 
D) The positive charge is localized on only one of the hydrogen atoms. 
A) The positive charge is distributed over all of the atoms in the ion. 
B) The positive charge is localized only on the oxygen atom. 
C) The positive charge is distributed between the three hydrogen atoms only. 
D) The positive charge is localized on only one of the hydrogen atoms.

Question 9

The combined effect of many weak noncovalent interactions can be very significant in determining factors such as three-dimensional structure for large biological molecules.

Accepted Answer

A) True 
 B)False

Question 10

A molecule or ion is said to be hydrated when it ________.

Accepted Answer

A) is neutralized by water 
B) is surrounded by water molecules 
C) reacts and forms a covalent bond to water 
D) aggregates with other molecules or ions to form a micelle in water 
A) is neutralized by water 
B) is surrounded by water molecules 
C) reacts and forms a covalent bond to water 
D) aggregates with other molecules or ions to form a micelle in water

Question 11

The osmotic pressure of an aqueous solution depends on

Accepted Answer

A) the chemical nature of the solute. 
B) the molar concentration of solute. 
C) the hydrophobic effect of the solute. 
D) All of the above. 
E) None of the above. 
A) the chemical nature of the solute. 
B) the molar concentration of solute. 
C) the hydrophobic effect of the solute. 
D) All of the above. 
E) None of the above.

Question 12

Acetic acid has a pKa of 4.8.How many milliliters of 0.2 M acetic acid and 0.2 M sodium acetate are required to prepare 1 liter of 0.1 M buffer solution having a pH of 4.8?

Accepted Answer

A) 500 ml acetic acid and 500 ml sodium acetate. 
B) 250 ml acetic acid and 250 ml sodium acetate,then 500 ml water. 
C) 250 ml acetic acid and 500 ml sodium acetate,then 250 ml water. 
D) 500 ml acetic acid and 250 ml sodium acetate,then 250 ml water. 
A) 500 ml acetic acid and 500 ml sodium acetate. 
B) 250 ml acetic acid and 250 ml sodium acetate,then 500 ml water. 
C) 250 ml acetic acid and 500 ml sodium acetate,then 250 ml water. 
D) 500 ml acetic acid and 250 ml sodium acetate,then 250 ml water.

Question 13

Which of the following is NOT a "weak" interaction?

Accepted Answer

A) Hydrogen bonds 
B) Van der Waals forces. 
C) Disulfide bonds. 
D) Ionic interactions. 
E) Hydrophobic interactions. 
A) Hydrogen bonds 
B) Van der Waals forces. 
C) Disulfide bonds. 
D) Ionic interactions. 
E) Hydrophobic interactions.

Question 14

The attractive force between two atoms is maximized when they are separated by the sum of their van der Waals radii.

Accepted Answer

A) True 
 B)False

Question 15

Which is true about hydrogen bonding for biological molecules?

Accepted Answer

A) Hydrogen bonds are strong enough to confer structural stability,for example in DNA. 
B) Hydrogen bonds are weak enough to be easily broken (weaker than covalent bonds). 
C) They contribute to the water solubility of many macromolecules. 
D) All of the above. 
A) Hydrogen bonds are strong enough to confer structural stability,for example in DNA. 
B) Hydrogen bonds are weak enough to be easily broken (weaker than covalent bonds). 
C) They contribute to the water solubility of many macromolecules. 
D) All of the above.

Question 16

Two weak acids,A and B,have pKa values of 4 and 6,respectively.Which statement is true?

Accepted Answer

A) Acid A dissociates to a greater extent in water than acid B. 
B) For solutions of equal concentration,acid B will have a lower pH. 
C) B is the conjugate base of A. 
D) Acid A is more likely to be a polyprotic acid than acid B. 
E) The equivalence point of acid A is higher than that of acid B. 
A) Acid A dissociates to a greater extent in water than acid B. 
B) For solutions of equal concentration,acid B will have a lower pH. 
C) B is the conjugate base of A. 
D) Acid A is more likely to be a polyprotic acid than acid B. 
E) The equivalence point of acid A is higher than that of acid B.

Question 17

Electrolytes dissolve readily in water because

Accepted Answer

A) they are held together by electrostatic forces. 
B) they are hydrophobic. 
C) water molecules can cluster about cations. 
D) water molecules can cluster about anions. 
E) water molecules can cluster about cations and anions. 
A) they are held together by electrostatic forces. 
B) they are hydrophobic. 
C) water molecules can cluster about cations. 
D) water molecules can cluster about anions. 
E) water molecules can cluster about cations and anions.

Question 18

Which of the following weak interactions is NOT an electrostatic interaction?

Accepted Answer

A) Hydrogen bonds. 
B) Charge-charge interactions. 
C) Hydrophobic interactions. 
D) Van der Waals forces. 
A) Hydrogen bonds. 
B) Charge-charge interactions. 
C) Hydrophobic interactions. 
D) Van der Waals forces.

Question 19

Basic solutions form when chemicals are dissolved in water and remove

Accepted Answer

A) OH-. 
B) H+. 
C) Na+. 
D) A and B. 
E) A,B and C. 
A) OH-. 
B) H+. 
C) Na+. 
D) A and B. 
E) A,B and C.

Question 20

Which is NOT a proper way to form a hydrogen bond? (The symbol "R" represents a general organic group.The hydrogen bonding is represented by dashed lines. )

Accepted Answer

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

Exam 2: Water

A titration curve for a weak acid is shown.Which point shows the most buffering?

Since the pKa of acetic acid is 4.8,it can be used to prepare a buffer to maintain physiological pH.

Proteins dissolved in water can be hydrolyzed by nucleophilic attack from the water molecules.

A solution containing 10-⁸ M HCl and 10-⁸ M acetic acid contains H+ which is supplied mostly by

Which would you expect to be most soluble in water?

In the detergent sodium dodecyl sulfate,the sulfate groups are very hydrophobic.

Which substance do you expect to be most soluble in water?

Which statement best characterizes the distribution of charge in the hydronium ion,H₃O+?

The combined effect of many weak noncovalent interactions can be very significant in determining factors such as three-dimensional structure for large biological molecules.

A molecule or ion is said to be hydrated when it ________.

The osmotic pressure of an aqueous solution depends on

Acetic acid has a pKa of 4.8.How many milliliters of 0.2 M acetic acid and 0.2 M sodium acetate are required to prepare 1 liter of 0.1 M buffer solution having a pH of 4.8?

Which of the following is NOT a "weak" interaction?

The attractive force between two atoms is maximized when they are separated by the sum of their van der Waals radii.

Which is true about hydrogen bonding for biological molecules?

Two weak acids,A and B,have pKa values of 4 and 6,respectively.Which statement is true?

Electrolytes dissolve readily in water because

Which of the following weak interactions is NOT an electrostatic interaction?

Basic solutions form when chemicals are dissolved in water and remove

Which is NOT a proper way to form a hydrogen bond? (The symbol "R" represents a general organic group.The hydrogen bonding is represented by dashed lines. )

Introduction to Biochemistry

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

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