61. Which symbol is used to denote the coupling between non-equivalent hydrogen atoms on adjacent carbon atoms in NMR spectroscopy?
(A)J
(B)Hz
(C)δ
(D)eV
(E) ppm

57. An ideal gas undergoes a reversible isothermal expansion. The change in entropy △S of the gas versus the volume of the gas is shown on the right. When Y'is expanded from 0.5m3 to 2 m3. △S =3 J/K. How many moles are in the sample? (The gas constant is R-8.3 J.K-1·mol-1)(A) 10 mol (B) 49.8 mol (C) 0.26 mol (D) 3.74 mol (E) 104.3 mol

58. An ideal monatomic gas undergoes the following reversible process (a→b). How much energy of heat is absorbed by the gas?(A)T0S0 (B)T0S0/2 (C)4T0S0 (D)3T0S0/2 (E)0

59. Two conducting spheres with radius r and 3r are separated far-apart. The larger sphere carries charge Q, while the smaller one is neutral. After the two spheres are connected by a conducting wire, what are the charges QS and QL carried by the smaller sphere and larger sphere, respectively? (A) QS = 15Q/16 andQL = Q/16 (B) QS = 9Q/10 and QL = Q/10 (C) QS = Q/10 and QL= 9Q/10 (D) QS = Q/16 andQL= 150/16 (E) QS = Q/4 and QL= 3Q/4

60. What is the electrical oscillations angular frequency in an inductance-capacitor circuit? Assume L is the inductance and C is capacitance.(A)(B)(C)(D)(E)

62. What is the role of AlCl3 in the reaction of benzene and Cl2? (A) To act as a nucleophile (B) To act as an electrophile (C) To strengthen the Cl–CI bond (D) To increase the reactivity of the electrophile (E) To act as a neutral species

63. Which of the following methods can be used to determine the molecular weight of a protein?Ⅰ: Sodium dodecyI sulfate-polyacrylamide gel electrophoresis； Ⅱ: Size-exclusion chromatography； Ⅲ: Electrospray ionization mass spectrometry； IV: Infrared spectroscopy； V: Ultraviolet-visible spectroscopy (A) Ⅰ, Ⅱ, Ⅲ, IV,V (B) Ⅰ,Ⅱ, Ⅲ, IV (C)  Ⅰ, Ⅱ, Ⅲ (D) Ⅰ, Ⅱ (E) Ⅰ

64. Boron consists of two isotopes, 10B and 11B. Chlorine also has two isotopes, 35CI and 37CI. Consider the mass spectrum of BCl3. How many peaks would be present? (A)7 (B)8 (C)9 (D) 10 (E) 11 

65. Which of the following statements about I D NMR and 2D NMR spectroscopy is INCORRECT? (A) ID NMR is faster than 2D NMR. (B) ID NMR gives less information than 2D NMR. (C) 2D NMR spectrum provides information about the spatial relationships between different nuclei in the sample, such as the distances and angles between atoms. (D) 2D NMR distinguishes between the overlapping signals that exist in larger molecules. (E) The advantage of 2D NMR spectroscopy is that it requires only one frequency axis.

66. The half-life of 14C is 5730 years. A sample taken for radiocarbon dating has been found to contain56 % of its original 14C. Which of the following options is the best estimate for the age of the sample? (Radioactive decay of 14C follows first-order kinetics.) (A)4.8x102(B) 4.8x103(C) 4.8x 105(D) 4.8 x 106(E) 4.8 x 100

67. Sort the molecules in the order from the largest bond angle to the smallest bond angle: H2O, NH3, BF3, CH4, CO2 (A) CH4, CO2, H2O, BF3, NH3 (B) CO2, BF3, CH4, NH3,H2O (C) NH3, H2O, BF3, CO2, CH4 (D) H2O, NH3, BF3, CH4, CO2 (E) BF3, NH3,  H2O, CH4, CO2