71. Nitrogen gas (N₂) reacts with hydrogen gas (H₂) to form ammonia (NH₃). At 200°C in a closed container, 1.2 atm of nitrogen gas is mixed with 2.3 atm of hydrogen gas. At equilibrium, the total pressure is 2.1 atm. Calculate the partial pressure of hydrogen gas at equilibrium.
(A) 2.3 atm
(B) 0.0 atm
(C) 1.8 atm
(D) 0.20 atm
(E) 0.92 atm

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.

72. The corrosion of which transition metal results in a characteristic green patina? (A) lead (B) copper (C) chromium (D) silver (E) iron

73. EDTA is an example of a(n) _____ ligand. (A) hexadentate (B) bidentate (C) octadentate (D) tetradentate (E) tridentate

74. When a molecule absorbs a photon, the molecule is promoted to an excited state M＊. The rate at which M＊ is created is proportional to the concentration of M. There are three pathways that M* may take to return to the ground state. Which statement about these three pathways below is wrong? (A) The rate at which the excited state returns to the ground state is independent of the pathway to the ground state and the concentration of excited state molecules. (B) The three possible pathways to return to the ground state are emission, deactivation, and quenching. (C) Quenching occurs when a second molecule, the quencher Q, collides with M* and energy is transferred from M* to Q: M* + Q→M+Q*. (D) Deactivation returns M* to the ground state by colliding with other molecules and releasing energy in the form of heat: M* → M + heat. (E) Emission returns M* to the ground state by emitting a photon: M* → M + hv.

75. A novel analytical method named ______ may enhance the fluorescence of immunoassays by a factor of 100 by measuring the fluorescence of Eu3+ 200 us after excitation with a laser pulse. (A) time-resolved fluorescence immunoassay (B) time-dependent fluorescence immunoassay (C) immunoassay fluorescence over time immunoassay (D) weakly bound time fluorescence immunoassay (E) europium-bound fluorescence immunoassay

76. Given that S = 131 J/K mol for H2(g), estimate the value of AS for the reaction: Ti(s) + H2(g) → TiH2(s) (A) 0 J/K (B) 131 J/K (C) -131 J/K (D) 262 J/K (E) -262 J/K

77. Which of the following exhibits the correct (increasing) orders for the atomic radius r and the ionization energy (IE), respectively? (A) r: F＜S＜O, IE: O ＜ S ＜F (B) r: F＜O ＜ S, IE: S ＜O ＜F (C) r: S＜O＜ F, IE: F ＜ O ＜S (D) r: S＜F＜ O, IE: S ＜ F ＜0 (E) none of the above