CHEMISTRY 102 FALL 2003 FINAL EXAM FORM C S DR. KEENEY-KENNICUTT PART 1

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1 NAME CHEMISTRY 102 FALL 2003 FINAL EXAM FORM C S DR. KEENEY-KENNICUTT Directions: (1) Put your name and signature on the free response part of the exam where indicated. (2) Choose the best answer for the multiple choice questions. If there is an ambiguous multiple choice question, use the last page to explain your answer. (3) Do NOT write on the envelope. (4) Bubble in OPTION A on the scanning sheet IF you want your grade posted. (5) When finished, put the free response answers in the envelope with the scanning sheet. You can keep the multiple choice part - the answers will be given to you as you leave. (6) The multiple choice questions are worth 5 points each (total of 55 questions). PART 1 1&2. Which is the correct K c expression for the equilibrium: 2C(s) + O 2 (g) 2CO(g)? (a) K c = 2[CO] 2[C][O 2 ] (d) K c = [CO]2 [O 2 ] (b) K c = [C]2 [O 2 ] [CO] 2 (e) K c = [O 2] [CO] 2 (c) K c = [CO]2 [C] 2 [O 2 ] 3&4. Complete and balance the following equation. The missing term is Pd + 1 0n Rh + (a) proton (b) positron (c) beta particle (d) neutron (e) alpha particle 5&6. PbS would be least soluble in (a) 0.10 M Pb(NO 3 ) 2 (b) 0.10 M Na 2 S (c) 0.10 M PbClO 3 (d) 0.10 M K 2 S (e) It is equally soluble in all of these solutions. 7&8. Any isomer of normal heptane has a total of carbon atoms. (a) 5 (b) 6 (c) 7 (d) 8 (e) it depends on the compound Keeney-Kennicutt, 2003 C 1

2 9&10.Which of the following statements is(are) FALSE? (I) H o f 298 for HF(g) = H o f 298 for HF(aq) (II) When w = 0, E = q at constant volume. (III) H = G + T S at constant temperature. (a) I only (b) I and III (c) III only (d) II only (e) I and II 11&12. The particle with the largest charge and the weakest penetrating power is the. (a) proton (b) positron (c) beta particle (d) alpha particle (e) gamma ray 13&14. Consider the gaseous system: N 2 + O 2 2NO... with H o = kj/mol rxn Which of the following will cause an increase in the equilibrium concentration of O 2? (a) Removing N 2 from the system. (b) Increasing the volume of the system. (c) Removing NO from the system as it is formed. (d) Increasing the temperature of the system. (e) Adding a catalyst. 15&16. Of the following species, which is the WEAKEST reducing agent? (a) V (b) Zn (c) Co (d) Cu (e) Sn 17&18. For the following ELECTROLYTIC cell, which of the following statements is incorrect? Cu 2+ (aq) + 2Br - (aq) Cu(s) + Br 2 (aq) (a) The anode is the electrode where oxidation occurs. (b) Electrons will flow away from the copper electrode through the wire as the cell operates. (c) The copper electrode is negatively charged. (d) The concentration of Br (aq) will decrease as the cell operates. (e) The reaction will have a positive value of G. Keeney-Kennicutt, 2003 C 2

3 19&20. Which of the following solutions is a buffer? (a) 0.1 M HClO 3 and 0.2 M NaClO 3 (b) 0.1 M NaOH and 0.1 M NaF (c) 0.1 M HCl and 0.2 M NaCl (d) 0.1 M HCN and 0.2 M NaCN (e) 0.1 M NH 3 and 0.1 M NaCl 21&22 Given that a reaction releases energy and has an activation energy of 30 kj/mol, which of the following statements are correct? (Hint: Draw the potential energy diagram.) (a) (1) and (4) (b) (2) and (4) (c) (3) and (4) (d) (2) and (5) (e) (3) and (5) (1) The reverse reaction has an activation energy equal to 30 kj/mol. (2) The reverse reaction has an activation energy less than 30 kj/mol. (3) The reverse reaction has an activation energy greater than 30 kj/mol. (4) The change in internal energy for the forward reaction is less than zero. (5) The change in internal energy for the forward reaction is greater than zero. 23&24. Suppose the reaction: A + 2B AB 2 occurs by the following mechanism: Step 1 A + B AB slow Step 2 AB + B AB 2 fast Overall A + 2B AB 2 The rate law expression must be Rate =. (a) k[a] (b) k[a][b] (c) k[b] (d) k[b] 2 (e) k[a][b] 2 Keeney-Kennicutt, 2003 C 3

4 25&26. Which of the following is a strong acid? (a) HClO 4 (b) HBrO 2 (c) HClO (d) HF (e) H 3 PO 4 27&28. What is the enthalpy change of the reaction below at 298 K and 1 atm pressure? Fe 3 O 4 (s) + CO(g) 3FeO(s) + CO 2 (g) H o f 298 (kj/mol) (a) -263 kj (b) -50 kj (c) +54 kj (d) +109 kj (e) kj Keeney-Kennicutt, 2003 C 4

5 29&30. For a certain process at 227 o C, G o = kj and H o = kj. What is the entropy change for this process at this temperature? (a) -3.1 J/K (b) +3.1 J/K (c) -6.5 J/K (d) +6.5 J/K (e) -7.9 J/K 31&32. Rate data were collected for the following reaction at a particular temperature. What is the value of the specific rate constant? NO 2 (g) + CO(g) NO(g) + CO 2 (g) Experiment [NO 2 ] initial [CO] initial Initial Rate of Reaction M 0.10 M M/s M 0.10 M M/s M 0.20 M M/s (a) M -1 s -1 (b) 0.50 M -1 s -1 (c) s -1 (d) 50. M -2 s -1 (e) 5.0 M -1 s -1 Keeney-Kennicutt, 2003 C 5

6 33&34. For how many hours should an electric current of 1.50 amp be passed to produce 20.0 g of chromium on a steel object from a solution containing chromium(iii) ions if the electrode efficiency is 65.0%? (a) 6.9 hr (b) 20.9 hr (c) 27.5 hr (d) 31.7 hr (e) hr 35&36 How much heat energy is liberated when 15.0 grams of iron metal is converted to Fe 2 O 3 (s) at standard state conditions? H o f 298 of Fe 2 O 3 (s) is _ kj/mol. (a) 83.9 kj (b) 167 kj (c) 985 kj (d) 228 kj (e) 111 kj Keeney-Kennicutt, 2003 C 6

7 37&38. What is the approximate ph of a solution that is 0.20 M in HNO 2 and 0.40 M in KNO 2? (a) 3.65 (b) 3.22 (c) 2.83 (d) 3.45 (e) &40. Suppose you have 100 ml of a M Mg(NO 3 ) 2 solution. If solid sodium hydroxide, NaOH, is slowly added to the beaker, at what ph would precipitation begin? (a) 8.13 (b) 7.00 (c) (d) 7.85 (e) 6.11 Keeney-Kennicutt, 2003 C 7

8 41&42. What is the ph of 0.25 M NH 4 Cl? (a) 5.10 (b) 5.65 (c) 5.35 (d) 4.51 (e) &44. What is the minimum mass required (in grams) of magnesium fluoride for the formation of 1.00 liter of its saturated solution? (a) 0.16 g (b) g (c) g (d) g (e) g Keeney-Kennicutt, 2003 C 8

9 45&46. Consider the following equilibrium in which the K c = HBr(g) H 2 (g) + Br 2 (g) Initially, there is 0.20 M of HBr. At equilibrium, what is the concentration of H 2? (a) M (b) M (c) 0.11 M (d) 0.18 M (e) 0.25 M 47&48. The half life of Pa-231 is 3.25 x 10 4 years. How many years will it take to have only 25.0% of a 1.00 gram sample remain? (a) 3.25 x 10 4 years (b) 9.75 x 10 4 years (c) 5.50 x 10 4 years (d) 6.50 x 10 4 years (e) 1.25 x 10 5 years Keeney-Kennicutt, 2003 C 9

10 49&50. The ph of a M solution of an unknown weak monoprotic acid is What is the K a of the unknown acid? (a) 1.6 x 10-6 (b) 2.9 x 10-6 (c) 1.3 x 10-5 (d) 4.0 x 10-6 (e) 7.9 x &52. Calculate the ph of a M solution of Sr(OH) 2. (All the sucker answers are present). (a) (b) (c) (d) 2.10 (e) 2.40 Keeney-Kennicutt, 2003 C 10

11 CHEMISTRY 102 FINAL EXAM Form C FALL 2003 S NAME Section Signature PART 2 (11 pts) 53. (a) Draw the voltaic cell that results when the following two half-cells are connected: (1) a gold electrode is inserted into a solution of M Au 3+ ions. (2) a silver electrode is inserted into a solution of M Ag + ions. Which is the anode and what is the anodic reaction? Which is the cathode and what is the cathodic reaction? What is the sign on each electrode? Show the direction of the electron flow. What is the overall reaction? (5 pts) (b) Write the shorthand notation for this cell. (5 pts) (c) Calculate the equilibrium constant for the overall reaction. Keeney-Kennicutt, 2003 C 11 OVER

12 (5 pts) 53. (d) Calculate the G o for this reaction. (5 pts) (e) What is the potential of this non-standard cell? (4 pts) 54. Circle all the functional groups you see on the compound below and clearly identify each one. (5 pts) 55. Clearly draw the cis geometric isomer of 3,4,4-trimethyl-2-hexene. Keeney-Kennicutt, 2003 C 12

13 SCRAP PAPER OR COMMENTS ON THIS EXAM Keeney-Kennicutt, 2003 C 13

CHEMISTRY 102 FALL 2010 FINAL EXAM FORM C Section 502 DR. KEENEY-KENNICUTT PART 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.