Biochemistry Module 2 Exam Questions & Answers

The pH of a solution of 3.2 x 10-10 M NaOH is: A. 3.7 B. 3.7 x 10-10 C. 4.5 D. 13 E. 8.7 - ANSWERSC. 4.5 Which attribute contributes to water's unusual properties? A. The geometry of the molecule B. The polarity of the O-H bonds C. The ability of water molecules to hydrogen bond D. The bond angle of water E. All of the answers are correct - ANSWERSE. All of the answers are correct What factor contributes to the bent shape of a water molecule? - ANSWERSThe unshared electron pairs on the oxygen atom Which diagrams correctly represent a hydrogen bond? - ANSWERSA and D The H+ concentration of a solution is 5.6 x 10-5 What is the pH? - ANSWERS4.25 If the Ka of an acid is 7.45 x 10-10, what is the pKa? - ANSWERS9.13 List the acids in INCREASING order of strength (weakest to strongest): Nitrous acid (Ka = 4.0 x 10-4); acetic acid (Ka = 1.7 x 10-5); phosphoric acid (Ka = 7.3 x 10-3) - ANSWERSAcetic acid, nitrous acid, phosphoric acid Elemental bromine (Br2) is a liquid at room temperature. What is the dominant attractive force that exists between Br2 molecules in the liquid? - ANSWERSLondon Forces Which one of the following molecules can form a hydrogen bond? A. HI B. HCl C. N2 D. CH4 E. H2O - ANSWERSC. N2 A hydrogen bond can form between a hydrogen atom bonded to oxygen, O-H, and ________. - ANSWERSN 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? - ANSWERSThe arrow points from N toward Br The following reaction occurs in glues purchased from hardware stores. Customers use this product to glue plastic together. Epoxy (l) + hardener (l) ⟶ Glue (s) + heat given off What is the sign (+ or -) of the change in ΔG and ΔH? A) ΔG is (+) and ΔH is (-) B) ΔG is (-) and ΔH is (-) C) ΔG is (-) and ΔH is (+) D) ΔG is (+) and ΔH is (+) E) None of the above - ANSWERSB. ΔG is (-) and ΔH is (-) Which of the following is the free-energy change of a reaction? A) ΔG B) ΔS C) ΔH D) ΔF E) All of the above - ANSWERSA. ΔG Which of the following is the change in entropy of a reaction? A) ΔG B) ΔE C) ΔH D) ΔF E) None of the above - ANSWERSE. None of the above Which buffer system is used by the renal system to maintain pH balance? - ANSWERSBicarbonate buffer system A buffer can neutralize only a certain amount of acid and base. We say that this is its: - ANSWERSBuffer Capacity