66. Give the effusion time of 250 mL of methane through a small hole is 48 s. How long will it require for same volume of helium to pass through the same hole? (CH4=16 g/mol； He=4 g/mol)
(A) 12 s
(B) 24 s
(C) 48 s
(D) 96 s
(E) 192 s

62. Given the electron configuration of an element X is [Ar]3d104s2 4p3 . What is the formula for the chloride of X most likely to be? (A) XCl (B) XCl2 (C) XCl3 (D) XCl4 (E) XCl6

63. How much energy is needed to convert 100 g of ice at 0℃ to water at 50℃?  specific heat capacity (ice) = 2.10 J/g· ℃；  specific heat capacity (water) = 4.18 J/g· ℃；  heat of fusion = 333 J/g；heat of vaporization = 2258 J/g (A) 10.1 kJ (B) 20.7 kJ (C) 31.4 kJ (D) 54.2 kJ (E) 65.8 kJ

64. What concentration of glucose in water is needed to produce an aqueous solution isotomic with blood? Give the osmotic pressure of blood at 25℃ is 7.70 atm. (R = 0.082 atm·L/mol·K) (A) 0.158 M (B) 0.315 M (C) 0.630 M (D) 1.580 M (E) 3.15 M

65. Which of the followings is not necessary for protein synthesis at the stage of peptide bonds formation? (A) amino acids (B) mRNA (C) DNA (D) tRNA (E) ribosomes

67. Given the second half-life for a second order reaction is 60 seconds. How much time is required for 87.5% reactant to be consumed in this reaction? (A) 30 seconds (B) 60 seconds (C) 90 seconds (D) 120 seconds (E) 210 seconds

68. Which of the following trends is incorrect? (A) atom size: Li ＜ Na ＜ K ＜ Cs (B) ion size: Ca2+ ＜ K+ ＜ Cl– ＜ S2– (C) electronegativity: I ＜ Br ＜ Cl ＜ F (D) boiling point: H2O ＜ H2S ＜ H2Se ＜ H2Te (E) bond angle: SbF3 ＜ AsF3 ＜ PF3 ＜ NF3

69. At 27℃, an ideal gas with a mass of 0.4 g in 100 mL has a pressure of 0.3 atm. What is the molecular weight of this gas molecule? (R = 0.082 atm·L/mol·K) (A) 328 (B) 246 (C) 133 (D) 120 (E) 30

70. The rate constant for a reaction increases from 10.0 s-1 to 100.0 s-1 when the temperature is increased from 300 K to 400 K. What is the activation energy for this reaction in kJ/mol?(R = 8.31 J/mol·K； ln10 = 2.30) (A) 45.6 (B) 23.0 (C) 18.3 (D) 12.7 (E) 5.0

71. Below reaction was studied at –10℃ and the following results were obtained. Considering the rate law of this reaction, what’s the unit of the rate constant? (A) (mol/L)2 ·min-1 (B) (mol/L)1 ·min-1 (C) (mol/L)0 ·min-1 (D) (mol/L)-1 ·min-1 (E) (mol/L)-2 ·min-1

72. Which of the following statements is correct? (A) Arrhenius postulated that an acid is a proton (H+) donor, and a base is a proton acceptor. (B) A buffer with a large capacity contains large volumes of the buffering components. (C) For the titrations of weak acids with strong bases, the greater pH value at the equivalence point is obtained when the stronger acid is used. (D) For a particular buffering system, all solutions that have the same ratio of [A– ]/[HA] have the same pH value. (E) An acid-base indicator can be used to determine the equivalence point of an acid-base titration because of its ability to mark the half-equivalence point of a titration by changing color.