Name ID# Section # CH EXAM Spring 7 - Form A Fill in your name, ID#, and section on this test booklet. Fill in and bubble in your name, ID# (bubble for C ), and section on the scantron form. For question #6 mark Mark the best answer after reading all possible choices. Use a # pencil and make clean erasures to insure proper scoring. When finished, turn in your scantron sheet and show this booklet and your CUID to the proctor. Questions are worth four points each except for the first two which are worth two points each. Good Luck! The first two questions are worth two points each. Consider the following mechanism for the conversion of propene to isopropyl alcohol. 4. Consider the following reversible reaction. The diagram represents an equilibrium mixture for this reaction.. In the mechanism shown, H 3 O + is a(n): reactant B. product intermediate catalyst. In the mechanism shown, the isopropyl cation is a(n): reactant B. product intermediate catalyst Which other diagram(s) represents a mixture at Mixture I Mixture II Mixture III I only B. II only III only I and III E. II and III 3. Copper-64 can decay to 64 Zn or 64 Ni. What are the modes of decay for these two reactions? 64 Cu 64 Zn 64 Cu 64 Ni + emission decay B. decay + emission e capture decay e capture + emission E. + emission e capture 5. Suppose the reaction U + n Ba + Kr +3 n 35 4 93 9 56 36 produces.664 kj/mol of energy. Calculate the change in mass in grams that occurs when one mole of U-35 reacts with one mole of neutrons? ( J = kg m /s ).85 g 5.4 g B..555 g E. 9. 7 g.898 g Page of 4
6. Consider the following equilibrium: CO(g) + 3 H (g) CH 4 (g) + H O(g) If K p =.6 5 at 4. K, calculate K c..4 7. 9 B..85 3 E.. 54 7. The reaction progress graph shown below is for a two-step process. The first step is while the step is the rate determining step in the mechanism. endothermic, first B. exothermic, first exothermic, second endothermic, second 8. Which is electron capture? B. E. Ge As + e 68 68 3 33 68 68 3 33 68 68 3 3 Ge + e As Ge + e Ga Ge + He Se 68 4 7 3 34 Ge Ga + e 68 68 3 3 9. With a change in temperature, a reaction acquires a new equilibrium constant (K) and a new rate law constant (k). What effect on K and k f does an increase in temperature have for the reaction below? N (g) + O (g) NO(g) K Energy Reaction Progress k f increase decrease B. increase increase decrease decrease decrease increase H rx = 8 kj. Upon balancing the nuclear reaction in which 3 Mg produces 3 Na plus one other particle, it is clear that B. E. e a positron emission. a e positron emission. e a beta decay. e a beta decay. e electron capture.. For a non-equilibrium mixture of hydrogen, iodine and hydrogen iodide at 5 C, G = 5.5 kj. What can be said about this system? H (g) + I (g) HI(g) G = 3.4 kj The forward reaction is favored and the system is close to equilibrium in that Q <. B. The forward reaction is favored and the system is far from equilibrium in that Q >. The system is at equilibrium. The reverse reaction is favored and the system is close to equilibrium in that Q <. E. The reverse reaction is favored and the system is far from equilibrium in that Q >.. A wooden archeological artifact was subjected to radiocarbon dating and was found to be 59 years old. Carbon-4 has a half-life of 575 years. A piece of modern day wood with same mass as the artifact contains 5.3 mg of C-4. What mass of C-4 does the artifact currently contain? 4. mg B..58 mg 6.4 mg.88 mg E. 9. mg 3. A sealed flask is charged with 36. atm of NO. What is the partial pressure of O at NO(g) N (g) + O (g) K p = 4 at ºC 94 atm 6. atm B. 35.7 atm E..5 x atm 7.9 atm Page of 4
4. Addition of hydrogen, H, gas to gaseous ethane, C H 4, with platinum catalyst, Pt(s), results in gaseous ethane, C H 6. Which statement is true if the temperature is held constant? The catalyst makes the equilibrium constant smaller. B. The catalyst makes the equilibrium constant larger. The catalyst does not affect the equilibrium constant. The catalyst affects only the forward reaction. E. The catalyst affects only the reverse reaction. 5. Which statement is true concerning these nuclear reactions? Reaction I: 36 U 37 Te + 97 Zr + n + energy Reaction II: H + H 3 He + energy Reaction I and II are both fission reactions. B. Reaction I and II are both fusion reactions. Reaction I is a fission reaction and Reaction II is a fusion reaction. Reaction I is a fusion reaction and Reaction II is a fission reaction. 6. Which of the following solutions will have the largest hydronium ion concentration, [H 3 O + ], at H 3 BO 3 (aq) + H O(l) H BO 3 (aq) + H 3 O + (aq) K = 5.4 B. H CO (aq) + H O(l) HCO (aq) + H 3 O + (aq) K =.8 4 H 3 S(aq) + H O(l) HS (aq) + H 3 O + (aq) K = 8.9 8 HCN(aq) + H O(l) CN (aq) + H 3 O + (aq) K = 6. 8. The activation energy for a reaction, is 75 kj while H = 7 kj. What is the activation energy for the reverse reaction? (Hint: Draw a progress of reaction diagram.) 75 kj 7 kj B. 38 kj E. kj 38 kj 9. For the following reaction and rate law: rate = k[h ][NO] H (g) + NO(g) N (g) + H O(g) Which mechanism(s) below is/are consistent with the observed rate law? mechanism I: H + NO H O + N N + NO N + O O + H H O mechanism II: H + NO N O + H O N O + H N + H O mechanism III: NO N O N O + H N O + H O N O + H N + H O I only B. II only III only I and II E. II and III equilibrium. Consider the thermal decomposition of mercuric oxide. HgO(s) Hg(l) + O (g) What is the equilibrium expression for the reverse reaction? 7. Po-8 decays in more than one step to Pb-. How many β and α events are involved in this process? 3 β and α B. β and 3 α β and α 3 β and α E. β and 3 α K= [Hg][O ] B. K= E. [Hg] [O ] K= [O ] K= [Hg] [O ] K= [O ] Page 3 of 4
. Which statement is correct regarding these two equilibrium systems? System I: Cl (g) + F (g) ClF(g) G = +5 kj System II: Cl (g) + I (g) ICl(g) G = 8 kj Both systems favor products. B. Both systems favor reactants. System I favors products but system II favors reactants. System I favors reactants but system II favors products.. For the following equilibrium reaction at 4 K, K C = 4.7: H O(g) + CH 4 (g) CO(g) + 3 H (g) If a mixture of.35 M H O,.5 M CH 4,.5 M CO and.75 M H is combined, in which direction will the reaction proceed to reach The system is at equilibrium and neither the forward reaction nor the reverse reaction is favored. B. The forward reaction will be favored until equilibrium is reached. The reverse reaction will be favored until equilibrium is reached. The concentrations of reactants and products will increase as equilibrium is reached. E. The concentrations of reactants and products will decrease as equilibrium is reached. 3. There are many proposed mechanisms for the destruction of ozone and one is shown below. Step Step ClO + ClO ClOOCl ClOOCl Cl + ClOO Step 3 ClOO Cl + O Step 4 Cl + O 3 ClO + O What is the reaction order for step (think molecularity) and the reaction order for step 3? Step Step 3 two one B. one two two two three one E. three two 4. What quantity of energy is released for alpha decay of 36 U? mass 4 He: 4.64 amu 3 Th: 3.384 amu 36 U: 36.45637 amu.473 8 kj/mol B. 4.48 8 kj/mol 4.99 8 kj/mol 7.9 8 kj/mol E. 4.99 kj/mol 5. NO is a toxic gas produced as a side product in combustion reactions. N (g) + O (g) NO (g) H rx = 66.4 kj Which is the best combination for minimizing the formation of this toxic material? Run the reaction at high temperatures in a large volume container. B. Run the reaction at high temperatures in a small volume container. Run the reaction at low temperatures in a large volume container. Run the reaction at low temperatures in a small volume container. 6. An equilibrium mixture of CO, O and CO at a certain temperature contains. M CO and.5 M O. At this temperature, Kc, equals.4 for the reaction: CO(g) + O (g) CO (g). What is the equilibrium concentration of CO? 4.8 6 M B.. 3 M 9.3 M 3. M 7. Pu-44 undergoes which type of nuclear decay reaction? alpha emission B. positron emission fusion beta emission E. electron capture 6. Mark A on your scantron. Page 4 of 4
USEFUL INFORMATION [A] t = kt + [A] ln [A] t = kt + ln[a] /[A] t = kt + /[A] t ½ = [A] k t ½ = ln k t ½ = [A] k k Ae E a RT E = mc c =.998 8 m/s J = kg m s mol = 6. 3 particles amu =.665 7 kg K p = K c (RT) n R =.86 L atm mol K R = 8.34 J/K mol G = G o + RT ln Q G o = RT ln K