66. A 0.20 M solution of MgSO4 has an observed osmotic pressure of 6.0 atm at 25°C. Determine the observed van't Hoff factor for this experiment.
(A) 1.23
(B) 2.00
(C) 1.66
(D) 1.80
(E) 1.45

62. Consider the following data concerning the equation: (A) Rate = k[H2O2][I– ][H+ ] (B) Rate = k[H2O2]2 [I– ]2 [H+ ]2 (C) Rate = k[I– ][H+ ] (D) Rate = k[H2O2][H+ ] (E) Rate = k[H2O2][I– ]

63. Which of the following statements are true? A catalyst can act in chemical reaction to: I. Lower the activation energy. II. Change the equilibrium concentration of the products. III. Decrease ΔE for the reaction. IV. Change the order of the reaction. V. Provide a new path for the reaction. (A) I, II, and III (B) II and III (C) II and V (D) I and V (E) III and IV

64. Which of the following statements is true about the following electrochemical cell? (A) The cell reaction is spontaneous with a standard cell potential of 0.06 V. (B) The cell reaction is nonspontaneous with a standard cell potential of –5.80 V. (C) The cell reaction is nonspontaneous with a standard cell potential of –0.06 V. (D) The cell reaction is spontaneous with a standard cell potential of 5.80 V. (E) The cell is at equilibrium.

65. Examine the phase diagram for the substance Bogusium (Bo) and select the correct statement. (A) Bo changes from a liquid to a gas as one follows the line from C to D. (B) The triple point for Bo is at a higher temperature than the melting point for Bo. (C) Bo changes from a solid to a liquid as one follows the line from C to D. (D) Point B represents the critical temperature and pressure for Bo. (E) Bo(s) has a lower density than Bo(l).

67. Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula? (A) C3H5O2 (B) C2HO3 (C) C2H5O4 (D) C3HO3 (E) C3H3O4

68. On a new temperature scale (°L), water boils at 155.00°L and freezes at –10.00°L. Calculate the normal human body temperature using this temperature scale. On the Celsius scale, normal human body temperature is 37.0°C, and water boils at 100.0°C and freezes at 0.0°C. (A) 57.30°L (B) 47.35°L (C) 51.05°L (D) 61.05°L (E) 41.05°L

69. When the following equation C2H5OH + O2⇌ CO2 + H2O is balanced, what are the coefficients? (A) 2, 3, 1, 4 (B) 1, 3, 2, 3 (C) 1, 1, 1, 1 (D) 1, 2, 3, 4 (E) 1, 2, 2, 2

70. To form a buffer solution with pH = 9.0, how many moles of NH4Cl should be added to 3.0 L of 0.20 M NH3(aq) at 25ºC? (Kb of ammonia = 1.8 × 10‒5 ; assuming the volume of solution does not change after adding NH4Cl) (A) 0.36 (B) 0.72 (C) 1.08 (D) 3.6 (E) None of the above.

71. Which statement about hydrogen bonding is true? (A) Hydrogen bonding is the intermolecular attractive forces between two hydrogen atoms in solution. (B) The hydrogen bonding capabilities of water molecules cause CH3CH2CH2CH3 to be more soluble in water than CH3OH. (C) Hydrogen bonding of solvent molecules with a solute will not affect the solubility of the solute. (D) Hydrogen bonding interactions between molecules are weaker than the covalent bonds within the molecule. (E) Hydrogen bonding arises from the dipole moment created by the equal sharing of electrons within certain covalent bonds within a molecule.

72. How many effective atoms are there in a body-centered cubic unit cell? (A) 1/2 (B) 1 (C) 2 (D) 3/2 (E) 3