複選題
37.Which of the following statements is not true?
(A)trans-1,3-dimethylcyclohexane is more stable than cis –1,3-dimethylcyclohexane.
(B)trans-1,2-dimethylcyclohexane is more stable than cis–1,2-dimethylcyclohexane.
(C)trans-1,4-dimethylcyclohexane is more stable than cis–1,4-dimethylcyclohexane.
(D)trans-1,2-dimethylcyclohexane is more stable than cis–1,3-dimethylcyclohexane.
(E)trans-1,2-dimethylcyclohexane is less stable than cis–1,3-dimethylcyclohexane. 

33.Which of the following molecules has the highest bond order? (A)BN (B)CO (C)NO (D)Ne2 (E)F2

34.According to the VSEPR theory, which of the following statements is correct? (A) The expected geometry of TeO32- is trigonal planar. (B) The expected geometry of SbBr 4 3- is tetrahedral. (C) The expected geometry of SeS24- is bent. (D) The expected geometry of BiCl3 is pyramidal. (E) The expected geometry of SnI42- is square planar.

複選題35.Which of the following statements is correct? (A)In O2, O22- , O2- , and O2+ species, only the O22- molecule is diamagnetic. (B)The stability decreases in the order O2+ > O2 > O2 - >O2 2- (C)The dissociation energy of N2 is larger than that of N2 + , while the dissociation energy of C2+ is smaller than that of C2. (D)In Mn2+, Cr3+, Hg2+ , V 3+, Ni2+, and La3+ six transition metal ions, only Mn2+ , V 3+, and La3+ are paramagnetic. (E)The atom size increases in the order K+ > Cl- > S2- , while the atom size of Au+ is larger than that of Au3+ .

36.Which of the following atoms is paramagnetic? (A)Cd (B)Tl1- (C)Nb1+ (D)Ni (E)Ru1+

38.The approximate pKa of NH3 is 36; that of C2H5OH is 16. From this information, which (if any) of the following conclusion is (or are) correct? (A)The conjugate base of C2H5OH is stronger. (B)The conjugate base of NH3 is stronger. (C)C2H5OH is a weaker acid than NH3 (D)None of the these is correct. (E)All of these are correct.

39.The activation energy(Eact) of a give reaction is unrelated to which of the following parameters? (A)The rate of the slowest step of a multistep reaction. (B)The rate of the overall teaction. (C)The heat absorbed or given off by the reaction (DH) (D)The stability of the transition state. (E)None of these.

40.Which of the following is least able to serve as a nucleophile in a chemical reaction? (A)Br- (B)OH- (C)NH3 (D)CH3+ (E)I-

41.Thiols are alcohol analogs in which the oxygen has been replaced by sulfur (e.g., CH3SH). Given the fact that the S-H bond is less polar than the O-H bond, which of the following statements comparing thiols and alcohols is correct? (A)Hydrogen bonding forces are weaker in thiols. (B)Hydrogen bonding forces are stronger in thiols (C)Hydrogen bonding forces would be the same. (D)No comparison can be made without additional information. (E)None of these.

42.Rank the transition states which occur during the following reaction steps in order of increasing stability (least→most stable): (a)CH3 - OH2+→CH3 + +H2O (b)(CH3)3C - OH2+→(CH3)3C + + H2O (c)(CH3)2CH - OH2+→(CH3)2CH+ + H2O (A)a < b < c (B)b < c < a (C)a < c < b (D)b < a < c (E)c < b < a

43.An alkane with a molecular formula C6H14 reacts with chlorine in the presence of light and heat. Four constitutionally isomeric monochlorides of molecular formula C6H13Cl are formed (along with a mixture of dichlorides, trichlorides, and so on). What is the most reasonable structure for the starting alkane? (A)CH3CH2CH2CH2CH2CH3 (B)(CH3)2CHCH2CH2CH3 (C)CH3CH(CH2CH3)2 (D)(CH3)3CCH2CH3 (E)(CH3)2CHCH(CH3)2