© Keeney-Kennicutt, 2010 C 1 NAME (Block Print)______________________________________ CHEMISTRY 102 FALL 2010 FINAL EXAM FORM C Section 502 DR. KEENEY-KENNICUTT Directions: (1) Put your name on PART 1 and your name and signature on PART 2 of the exam where indicated. (2) Sign the Aggie Code on PART 2 of this exam. (3) Each multiple choice question is actually 2 questions on your scanning sheet. If you are sure of an answer, put the same answer down for both questions for 5 pts. If you cannot decide between two answers, put your best answer down for the first (odd) question and the other answer down for the second (even) question. If you get the first one correct you'll get 3 pts; if you get the second one correct you’ll get 2 pts. If there is an ambiguous multiple choice question, use the last page to explain your answer. (4) Do NOT write on the envelope. (5) When finished, put everything in the envelope and wait to be excused. At the table, take everything out of the envelope. You can pick up the multiple choice part with the answers outside my office after the exam. (6) There are a total of 60 multiple choice questions (30 actual questions) plus 20 pts free response. PART 1 1&2. Which is the correct Kc expression for the equilibrium: Ni(s) + 4CO(g) →← Ni(CO)4(g) ? (a) Kc = [Ni(CO)4][Ni][CO] (b) Kc = [Ni][CO]4[Ni(CO)4] (c) Kc = [Ni(CO)4][CO]4 (d) Kc = [Ni(CO)4]4[CO] (e) Kc = [Ni(CO)4][Ni][CO]4 3&4. Which one of the following combinations cannot produce a buffer solution? (a) NH3 and NH4Br (b) NH3 and (NH4)2SO4 (c) HCN and NaCN (d) HNO2 and NaNO2 (e) HClO4 and NaClO4 5&6. Which of the following statements is FALSE about solubility and miscibility? (a) Iodine, I2(s), should be more soluble in carbon tetrachloride, CCl4, than water. (b) CsCl is more soluble in water than CaS. (c) In the phrase “Like dissolves like,” the term “like” refers to molecules with similar molecular weights. (d) Benzene, C6H6, is miscible in chloroform, CHCl3. (e) Water and methanol, CH3OH are miscible.© Keeney-Kennicutt, 2010 C 2 7&8. The best representation for the reaction whose heat of reaction is equal to the standard molar enthalpy of formation for CHCl3(g) is: (a) C(s,graphite) + ½ H2(g) + 3/2 Cl2(g) Æ CHCl3(g) (b) 2C(s,graphite) + H2(g) + 3 Cl2(g) Æ 2CHCl3(g) (c) CHCl3(g) Æ C(s,graphite) + ½ H2(g) + 3/2 Cl2(g) (d) 2CHCl3(g) Æ 2C(s,graphite) + H2(g) + 3 Cl2(g) (e) C(s,graphite) + H(g) + 3Cl(g) Æ CHCl3(g) 9&10. The rate law for the chemical reaction, 2ClO2(aq) + 2OH−(aq) → ClO3− (aq) + ClO2−(aq) + H2O(l) has been determined experimentally to be: Rate = k[ClO2]2[OH−] The reaction order with respect to the hydroxide ion is: (a) k[OH−]2 (b) k[ClO2]2[OH−] (c) 3 (d) 2 (e) 1 11&12. Consider the gas phase reaction: 2C + D → C2D, which occurs by the following mechanism: Step 1 C + C → C2 slow Step 2 C2 + D → C2D fast Overall 2C + D → C2D The rate law expression must be Rate = ________. (a) k[C][D] (b) k[C]2 (c) k[D] (d) k[C]2[D] (e) k[C] 13&14. Which one of the following statements is TRUE about the following reaction? HNO2 + H2O →← H3O+ + NO2− (a) There are no conjugate acid-base pairs. (b) OH− is the conjugate acid of H2O. (c) H2O is the conjugate base of OH−. (d) HNO2 is the conjugate acid of H2O. (e) NO2− is the conjugate base of HNO2. 15&16. For Ag3PO4, the relationship between Ksp and s, the molar solubility in mol/L, is (a) Ksp = s1/2 (b) Ksp = s2 (c) Ksp = 4s3 (d) Ksp = 8s4 (e) Ksp = 27s4© Keeney-Kennicutt, 2010 C 3 17&18. Consider the following gaseous phase system at equilibrium: N2O4(g) →← 2NO2 (g) ΔH = +58 kJ Which of the following changes will INCREASE the amount of NO2 at equilibrium? (a) adding N2(g) (b) increasing the temperature (c) decreasing the volume of the container (d) adding a catalyst (e) removing N2O4(g) 19&20. Which of the following statements is FALSE? (a) At absolute 0 K, the entropy of a pure perfect crystalline substance is zero. (b) Endothermic processes are those that absorb heat. (c) ΔS is a state function. (d) The system's enthalpy alone does not determine the spontaneity of a reaction. (e) A reaction is spontaneous if ΔSuniverse decreases. 21&22. In this titration, what is being titrated with what? (a) a weak acid is being titrated with a strong base (b) a weak base is being titrated with a strong acid (c) a strong acid is being titrated with a strong base (d) a strong base is being titrated with a strong acid (e) none of the above. 23&24. Which statement or statements are TRUE about catalysts? (1) Catalysts change the mechanism of a reaction. (2) A catalyst cannot appear as a reactant in a rate law expression. (3) A catalyst lowers the activation energy of both the forward and reverse reaction. (a) 1 & 2 (b) 2 & 3 (c) 1 & 3 (d) only 1 (e) only 3© Keeney-Kennicutt, 2010 C 4 25&26. Which statement is TRUE about aqueous solutions? (a) As the value of the van’t Hoff factor of the solute increases, the freezing point of the solution will increase. (b) When the molality of the solute doubles, the boiling point of the solution will double. (c) When a solute dissolves into the solvent, the vapor pressure of the solution will be lower than the vapor pressure of the pure solvent at a particular temperature. (d) A solution is a heterogeneous mixture in which no settling occurs. (e) A solution can only be made by dissolving a solid into a liquid. 27&28. Of the following species, which is the STRONGEST reducing agent? (a) Cr (b) Zn2+ (c) Cr2+ (d) Cu (e) Co2+ 29&30. Consider the following reaction and choose the correct statement: 2 H2O(l) + O2(g) → 2 H2O2(l) ΔHo = +196 kJ ΔSo = −126 J/K (a) The reaction becomes spontaneous as the temperature increases. (b) The reaction becomes spontaneous as the temperature decreases. (c) The reaction is spontaneous at all temperatures. (d) The reaction is nonspontaneous at all temperatures. (e) The temperature does not influence the spontaneity of any reaction. 31&32. Consider the equilibrium, B2 →← 2B with Kc >> 1. Which picture represents this system? (a) (b) (c) (d) (e)©