Biochemistry M2 Exam Questions And Answers
1. The pH of a solution of 0.0010 M NaOH is:: 11 (Kw=[H+][OH-] = 1.0 x 10-14;
[H+][0.0010] = 1.0 x 10-14 [H+]=1.0 x 10-11; pH=-log[1.0 x 10-11]=11)
2. Water is a unique molecule. Which of the following contributes to water's
unique place in the chemical world?: All of the answers are correct
3. The bent shape of water is due to .: The unshared electron
pairs on the oxygen atom
4. Which diagrams correctly represent a hydrogen bond?: A and D
5. The H+ concentration of a solution is 1.2 x 10-3 M. What is the pH?: 2.92
6. If the Ka of an acid is 5.63 x 10-3, what is the pKa?: 2.25 ([pKa = -log(5.63 x
10-3) = 2.25])
7. List the acids in DECREASING order of strength (strongest to weakest):
Nitrous acid (Ka = 4.0 x 10-4); acetic acid (Ka = 1.7 x 10-5); phosphoric acid
(Ka = 7.3 x 10-3): Phosphoric acid, nitrous acid, acetic acid
8. Elemental iodine (I2) is a solid at room temperature. What is the dominant
attractive force that exists between I2 molecules in the solid?: London forces
9. Which one of the following molecules can form a hydrogen bond? (A.) HBr
(B.) HCl (C.) NH3 (D.) CH4 (E.) H2: C. NH3
10. A hydrogen bond can form between a hydrogen atom bonded to oxygen,
O-H, and .: N
11. In a bond between P and Cl, there exists a difference in electronegativity
resulting in partial positive and partial negative charges. If a dipole arrow were
added to this structure, which way would the arrow point?: The arrow points
from N toward Br
12. The following reaction occurs in glues purchased from hardware stores.
Customers use this product to glue plastic together. Epoxy (l) + hardener (l) ö
Glue (s) + heat given off What is the sign (+ or -) of the change in ”G and ”H?:
G is (-) and ”H is (-)
13. Which of the following is the free-energy change of a reaction?: ”G
14. Which of the following is the change in entropy of a reaction?: None of the
above
15. : A
16. Which buffer system is used by the renal system to maintain pH balance?-
: Bicarbonate buffer system
17. A buffer can neutralize acid and base within a certain limit. We say that this
is its:: Buffer capacity
18. Is a pH of 8.36 acidic, neutral, or basic?: Basic
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1. The pH of a solution of 0.0010 M NaOH is:: 11 (Kw=[H+][OH-] = 1.0 x 10-14;
[H+][0.0010] = 1.0 x 10-14 [H+]=1.0 x 10-11; pH=-log[1.0 x 10-11]=11)
2. Water is a unique molecule. Which of the following contributes to water's
unique place in the chemical world?: All of the answers are correct
3. The bent shape of water is due to .: The unshared electron
pairs on the oxygen atom
4. Which diagrams correctly represent a hydrogen bond?: A and D
5. The H+ concentration of a solution is 1.2 x 10-3 M. What is the pH?: 2.92
6. If the Ka of an acid is 5.63 x 10-3, what is the pKa?: 2.25 ([pKa = -log(5.63 x
10-3) = 2.25])
7. List the acids in DECREASING order of strength (strongest to weakest):
Nitrous acid (Ka = 4.0 x 10-4); acetic acid (Ka = 1.7 x 10-5); phosphoric acid
(Ka = 7.3 x 10-3): Phosphoric acid, nitrous acid, acetic acid
8. Elemental iodine (I2) is a solid at room temperature. What is the dominant
attractive force that exists between I2 molecules in the solid?: London forces
9. Which one of the following molecules can form a hydrogen bond? (A.) HBr
(B.) HCl (C.) NH3 (D.) CH4 (E.) H2: C. NH3
10. A hydrogen bond can form between a hydrogen atom bonded to oxygen,
O-H, and .: N
11. In a bond between P and Cl, there exists a difference in electronegativity
resulting in partial positive and partial negative charges. If a dipole arrow were
added to this structure, which way would the arrow point?: The arrow points
from N toward Br
12. The following reaction occurs in glues purchased from hardware stores.
Customers use this product to glue plastic together. Epoxy (l) + hardener (l) ö
Glue (s) + heat given off What is the sign (+ or -) of the change in ”G and ”H?:
G is (-) and ”H is (-)
13. Which of the following is the free-energy change of a reaction?: ”G
14. Which of the following is the change in entropy of a reaction?: None of the
above
15. : A
16. Which buffer system is used by the renal system to maintain pH balance?-
: Bicarbonate buffer system
17. A buffer can neutralize acid and base within a certain limit. We say that this
is its:: Buffer capacity
18. Is a pH of 8.36 acidic, neutral, or basic?: Basic
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