64. How many unpaired electrons are there in an atom of oxygen in its ground state?
(A) 1
(B) 2
(C) 4
(D) 0
(E) 3

60. The light intensity incident on a metallic surface produces photoelectrons with a maximum kinetic energy of 2 eV. The light intensity is doubled. Determine the maximum kinetic energy of the photoelectrons (in eV). (A) 4 eV (B) 2 eV (C) √2 eV (D) 1 eV (E) 8 eV

61. Arrange the steps below in the order required to perform a Kjeldahl Nitrogen Analysis. I Distillation of ammonia into standard hydrochloric acid. II Neutralize ammonium to release ammonia.  III Digest the organic sample with boiling sulfuric acid to convert nitrogen to ammonium. IV Titrate unreacted standard hydrochloric acid with sodium hydroxide. (A) III, II, I, IV (B) II, I, IV, III (C) I, IV, III, II (D) IV, III, II, I (E) III, I, IV, II

62. What is the product of the following reaction? (A)(B)(C)(D)(E)

63. Stray light is a problem for spectrophotometers that are not tightly sealed. What is the main impact of stray light on the recorded absorbance? (A) The apparent absorbance is greater than the true absorbance and increases as the amount of stray light increases. (B) The apparent absorbance is greater than the true absorbance and decreases as the amount of stray light increases. (C) The apparent absorbance is less than the true absorbance and increases as the amount of stray light decreases. (D) The apparent absorbance is less than the true absorbance and decreases as the amount of stray light decreases. (E) It is impossible to determine effect of stray light on measured absorbance.

65. A crystal of NaCl is _____ (A) hard, high-melting, and a poor electrical conductor (B) hard, high-melting, and a good electrical conductor (C) soft, low-melting, and a good electrical conductor (D) soft, high-melting, and a poor electrical conductor (E) soft, low-melting, and a poor electrical conductor

66. Which of the following chemical or physical changes is an endothermic process? (A) the evaporation of water (B) the mixing of sulfuric acid and water (C) the freezing of water (D) the combustion of gasoline (E) none of the above

67. The _____ is the electrode at which the reaction of interest occurs. (A) auxillary electrode (B) counter electrode (C) anode (D) cathode (E) working electrode

68. Which of the shown molecules fits the fragmentation pattern of the mass spectrum below the best? (A)(B)(C)(D)(E)

69. Which of the following molecules is optically active? (A)(B)(C)(D)(E) none of the above

70. Rank the following compounds according to increasing solubility in water. I CH3-CH2-CH2-CH3 II CH3-CH2-O-CH2-CH3  III CH3-CH2-OH IV CH3-OH (A) I ＜II ＜ IV ＜ III (B) I ＜ III ＜ IV＜ II (C) I ＜II ＜ III ＜ IV (D) III ＜ IV ＜ II ＜ I (E) None of the above is correct.