Biochemistry M2 Exam Question with
Correct answers
The pH of a solution of 0.0010 M NaOH is: - Correct Answer: 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)
Water is a unique molecule. Which of the following contributes to water's unique place in the chemical
world? - Correct Answer: All of the answers are correct
The bent shape of water is due to ______________. - Correct Answer: The unshared electron pairs on
the oxygen atom
Which diagrams correctly represent a hydrogen bond? - Correct Answer: A and D
The H+ concentration of a solution is 1.2 x 10-3 M. What is the pH? - Correct Answer: 2.92
If the Ka of an acid is 5.63 x 10-3, what is the pKa? - Correct Answer: 2.25 ([pKa = -log(5.63 x 10-3) =
2.25])
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) - Correct Answer: Phosphoric acid, nitrous
acid, acetic acid
Elemental iodine (I2) is a solid at room temperature. What is the dominant attractive force that exists
between I2 molecules in the solid? - Correct Answer: London forces
Which one of the following molecules can form a hydrogen bond? (A.) HBr (B.) HCl (C.) NH3 (D.) CH4 (E.)
H2 - Correct Answer: C. NH3
A hydrogen bond can form between a hydrogen atom bonded to oxygen, O-H, and ________. - Correct
Answer: N
Correct answers
The pH of a solution of 0.0010 M NaOH is: - Correct Answer: 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)
Water is a unique molecule. Which of the following contributes to water's unique place in the chemical
world? - Correct Answer: All of the answers are correct
The bent shape of water is due to ______________. - Correct Answer: The unshared electron pairs on
the oxygen atom
Which diagrams correctly represent a hydrogen bond? - Correct Answer: A and D
The H+ concentration of a solution is 1.2 x 10-3 M. What is the pH? - Correct Answer: 2.92
If the Ka of an acid is 5.63 x 10-3, what is the pKa? - Correct Answer: 2.25 ([pKa = -log(5.63 x 10-3) =
2.25])
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) - Correct Answer: Phosphoric acid, nitrous
acid, acetic acid
Elemental iodine (I2) is a solid at room temperature. What is the dominant attractive force that exists
between I2 molecules in the solid? - Correct Answer: London forces
Which one of the following molecules can form a hydrogen bond? (A.) HBr (B.) HCl (C.) NH3 (D.) CH4 (E.)
H2 - Correct Answer: C. NH3
A hydrogen bond can form between a hydrogen atom bonded to oxygen, O-H, and ________. - Correct
Answer: N
