資訊推薦

• 42. If a molecule contains 4 elements of unsaturation and signals in the 1H NMR spectrum between δ
• 43. Using a 60 MHz spectrometer, the protons in dichloromethane appear at 5.30 ppm. When the same sa
• 44. Which of the following is another name for cyclobutadiene? (A)[2]annulene (B)[4]annulene (C) [6]
• 45. In electrophilic aromatic substitution reactions a bromine substituent ________. (A)is a deactiv
• 46. Which element is oxidized in the reaction below?Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) +
• 47. Which of the following reactions is a redox reaction?(a) K2CrO4 + BaCl2 → BaCrO4 + 2KCl(b) Pb22+
• 48. The purpose of the salt bridge in an electrochemical cell is to ________. (A)maintain electrical
• 49. Consider an electrochemical cell based on the reaction:2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g) Wh
• 50. What is the cathode in an alkaline battery? (A)MnO2 (B)KOH (C) Zn powder(D)Mn2O3
• 51. The standard cell potential ( ) for the reaction below is +0.63 V. At 25 °C, the cell potential
• 32. About a chemical reaction, which of the following statements is correct? (A) the entropy change
• 33. Which of the following compounds is a paramagnetic substance? (A) N2 (B) NH3 (C) NO2 (D) hydrazi
• 34. Which of the following electron configurations is not correct? (A) C:1s22s22p2 (B) Ne:1s22s22p6
• 35. Which of the following reactions do not produce HCI? (A) phosgene reacts with moisture (B) the a
• 36. An aqueous solution containing Ba2+, Pb2+, Cu2+, C3+and Hg22+ions is treated by HCI, H2S and NaO
• 37. How many pars of lone pair electrons dose the Xe atom of XeF4 possess? (A)1 (B) 2 (C)3 (D) 4 (E)
• 38. The coordination number of Cs in CsCl under ambient conditions is: (A)1 (B)2 (C)4 (D)6(E) 8
• 39. Which of the following elements has the highest electron affinity (most exothermic)? (A)O(B)F(C)
• 40. Which of the following statements is not correct for balancing the following chemical equation?a
• 52. The first law of thermodynamics can be given as ________. (A)ΔE = q + w (B)(C) for any spontaneo
• 53. When a system is at equilibrium, ________. (A)the reverse process is spontaneous but the forward
• 54. The second law of thermodynamics states that ________. (A)ΔE = q + w (B)ΔH°rxn = Σ nΔH°f (produc
• 55. ΔS is positive for the reaction ________. (A)2H2 (g) + O2 (g) → 2H2O (g) (B)2NO2 (g) → N2O4 (g)
• 56. With thermodynamics, one cannot determine ________. (A)the speed of a reaction (B)the direction
• 57. Photoionization processes (e.g., N2 + hν → N2+ + e-) remove UV of ＜ 150 nm. Which photoreaction