20. Which of the following is a Lewis acid?
(A) BCl₃
(B) CH₄
(C) NH₃
(D) CHCl₃
(E) None of the above are Lewis acids.

16. Which of the following compounds exhibits only dispersion and dipole-dipole intermolecular interactions? (A) H2 (B) HI (C) CO2 (D) CH3NH2 (E) CH3OH

17. Which of the following statements is TRUE? (A) The solubility of a solid is not dependent on either temperature or pressure. (B) The solubility of a solid is highly dependent on pressure. (C) The solubility of a solid is highly dependent on both pressure and temperature. (D) The solubility of a solid is highly dependent on temperature. (E) None of the above.

18. Consider the following reaction at equilibrium. What will happen if we add more SO3 in the system? SO2(g)+NO2(g)⇌ SO3(g)+NO(g) (A) The reaction will shift in the direction of products. (B) The reaction will shift to decrease the pressure. (C) No change will occur since SO3 is not included in the equilibrium expression. (D) The reaction will shift in the direction of reactants. (E) The equilibrium constant will decrease.

19. Which Br Φnsted-Lowry acid is not considered to be a strong acid in water? (A) HI (B) HBr (C) H2SO3 (D) HNO3 (E)HCI

21. When titrating a weak monoprotic acid with NaOH at 25℃, the (A) pH will be less than 7 at the equivalence point. (B) pH will be equal to 7 at the equivalence point. (C) pH will be greater than 7 at the equivalence point. (D) titration will require more moles of base than acid to reach the equivalence point. (E) titration will require more moles of acid than base to reach the equivalence point.

22. Which of the following statements is TRUE? (A) Entropy is not a state function. (B) Endothermic processes decrease the entropy of the surroundings, at constant T and P. (C) Endothermic processes are never spontaneous. (D) Exothermic processes are always spontaneous. (E) None of the above are true.

複選題23. What statement is NOT true about standard electrode potentials? (A) E° cell is positive for spontaneous reactions. (B) Electrons will flow from more negative electrode to more positive electrode. (C) The electrode potential of the standard hydrogen electrode is exactly zero. (D) E° cell is the difference in voltage between the anode and the cathode. (E) The electrode in any half-cell with a greater tendency to undergo reduction is positively charged relative to the standard hydrogen electrode and therefore has a positive E°.

24. What will happen during gamma ray emission. (A) The mass number and atomic number decrease. (B) The mass number and atomic number increase. (C) The mass number is unchanged and the atomic number decreases. (D) The mass number is unchanged and the atomic number increases. (E) The mass number and atomic number do not change.

25. Identify the element that is not used as a radioactive tracer. (A) iron-59 (B) phosphorus-32 (C) thallium-201 (D) iodine-131 (E) carbon-13

26. How many chiral centers are there in the following molecule? (A) 4 (B) 5 (C) 6 (D) 7