CHEMISTRY 112 FINAL EXAM June 24, 2013 FORM A 1. The following data was obtained for a reaction. The slope of the line is!2.8 " 10 3 K and the intercept is!0.44. What is the activation energy of the reaction? A. 0.366 kj/mol B.!0.366 kj/mol C. 2.8 kj/mol D.!23.3 kj/mol E. 23.3 kj/mol 2. If the electronic structure of a solid substance consists of a valence band that is completely filled with electrons and there is a large energy gap to the next set of orbitals, what type of substance will this be? A. alloy B. metal C. superconductor D. insulator E. semiconductor ln k 1/T (K!1 ) 3. The reactions below are given with their corresponding rate laws. Which one corresponds to an elementary processes? A. A + B # C; rate = k[a] 2 B. A + B # C; rate = k[a][b] 2 C. A + B # C; rate = k[b] D. A + B # C; rate = k[a] [B] E. 2A # C; rate = k[a] 4. The rate law for the reaction below is rate = k[h 2 O 2 ][I ]. H 2 O 2 (aq) + 2H + (aq) + 2I (aq) # I 2 + 2H 2 O(!) The following mechanism has been suggested. H 2 O 2 (aq) + I (aq) # HOI(aq) + OH (aq) (slow) OH (aq) + H + (aq) # H 2 O(!) (fast) HOI(aq) + H + (aq) + I (aq) # I 2 (aq) + H 2 O(!) What are the intermediates in this mechanism? A. H + (aq) and I (aq) B. H + (aq) and HOI(aq) C. HOI(aq) and OH (aq) D. H + (aq) only E. H 2 O(!) and OH (aq) (fast)

5. When atoms of beryllium-9 are bombarded with alpha particles, one neutron is produced per Be that disintegrates. What new isotope is also formed? A. 12 C B. 5 Li C. 8 Li D. 10 B E. 12 B 6. What is the poh of a 0.0085 M KOH solution? A. 2.1 B. 4.8 C. 9.2 D. 12.4 E. 13.1 7. Which one of these elements would give a p-type semiconductor when added to a silicon crystal? A. C B. P C. As D. Ga E. Sb 8. Which one of the following substances is not correctly paired with the type of solid it forms? heading heading A. graphite network covalent B. Na metallic C. SiO 2 molecular D. CaO ionic E. diamond network covalent 9. Which aqueous mixture would be a buffer system assuming 100 ml of 0.1 M solutions of each are mixed? A. i B. iii C. iv i. H 3 PO 4, NaOH ii. HNO 3, NaNO 3 iii. iv. D. ii and iv E. i and iv HCl, NaCl CH 3 COOH, CH 3 COONa

10. Which of the following species has the largest absolute entropy (Sº)? A. C (diamond) B. C (graphite) C. H 2 O (!) D. Br 2 (!) E. O 2 (g) 12. The reaction rates of many spontaneous reactions are actually very slow. Which of these statements is the best explanation for this observation? A. K eq for the reaction is less than one. B. The activation energy of the reaction is large. C. $G for the reaction is positive. D. The reaction is endothermic. E. The entropy change is negative. 11. What is the expression for the ion product for calcium phosphate, Ca 3 (PO 4 ) 2? A. [Ca 2+ ][PO 4 3! ] B. [Ca 2+ ] 2 [PO 4 3! ] 3 C. [Ca 2+ ] 3 [PO 4 3! ] 2 D. E.!"!!!"!!!!"!!!"!!!!"!!!!"!!!!!"!!!"!!! 13. What is the coordination number and oxidation state of the metal in this complex? [Pt(NH 3 ) 2 Cl 2 ] CN of metal Oxidation state of metal A. 4 0 B. 6 +2 C. 4 +2 D. 6 +4 E. 4 +4

14. The spectrochemical series (below) is the list of ligands in order of their ability to split d-orbitals. Cl! < OH < F! < H 2 O < NH 3 < en < NO 2! < CN! < CO Which one of the following ligands below is most likely to form a low-spin octahedral complex with iron(iii)? A. Cl B. H 2 O C. CN! D. OH E. CO 15. In the reaction below, what is oxidized and what is reduced? 3 I 2 (s) + 2 MnO 2 (s) + 8 OH (aq) # 6I (aq) + 2MnO 4 (aq) + 4H 2 O(!) oxidized reduced A. MnO 2 (s) I 2 (s) B. I 2 (s) MnO 2 (s) C. I 2 (s) H 2 O(!) D. OH (aq) I 2 (s) E. MnO 2 (s) OH (aq) 16. Eº for the following reaction is 0.13 V. What is the value of $Gº for the reaction? Pb(s) + 2H + (aq) # Pb 2+ (aq) + H 2 (g) A.!12 kj B. 12 kj C.!25 kj D. 25 kj E. 38 kj 17. Which, if any, of the following metals would be capable of acting as a sacrificial anode when used with iron pipe? The standard reduction potentials for each metal are given. E Fe = 0.44 V. A. copper, Cu E = +0.34 V B. cobalt, Co E = 0.28 V C. chromium, Cr E = 0.74 V D. tin, Sn E = 0.14 V E. None of these metals would be capable of acting as a sacrificial anode with iron.

18. The structure of a section of a polymer is shown below. Which one of the following is the monomer from which it was made? 20. What is the nuclear binding energy per nucleon for 25 Mg (atomic mass 24.985839 amu)? A. 3.30 " 10!8 J/nucleon B. 1.32 " 10 12 J/nucleon C. 0.22076 J/nucleon D. 0.999 J/nucleon E. 7.70 " 10 11 J/nucleon 21. A 0.15 M solution of chloroacetic acid has a ph of 1.86. What is the value of K a for this acid? 19. Tritium is the radioactive isotope of hydrogen. It decays with a first-order rate constant k of 0.056 year 1. What fraction of the tritium initially in a sample is still present 30 years later? A. 0.017 B. 0.15 C. 0.19 D. 0.60 E. 2.8 " 10 38 A. 7.2 " 10 1 B. 1.6" 10!1 C. 9.9" 10!2 D. 1.4" 10!3 E. 2.7" 10!4

22. Consider the weak bases below and their K b values: base K b C 6 H 7 O! 1.3 " 10 10 C 2 H 5 NH 2 5.6 " 10 4 C 5 H 5 N 1.7 " 10 9 Arrange the conjugate acids of these weak bases in order of increasing acid strength. A. C 5 H 5 NH + < C 6 H 7 OH < C 2 H 5 NH 3 + B. C 6 H 7 OH < C 5 H 5 NH + < C 2 H 5 NH 3 + C. C 5 H 5 NH + < C 2 H 5 NH 3 + < C 6 H 7 OH D. C 6 H 7 OH < C 2 H 5 NH 3 + < C 5 H 5 NH + E. C 2 H 5 NH 3 + < C 5 H 5 NH + < C 6 H 7 OH 23. What will happen when a 10g of KNO 2 is added to a 500.0 ml sample of 0.10 M HNO 2 solution? A. i B. ii C. iii i. The ph will increase. ii. The [NO 2! ] will increase. iii. The [HNO 2 ] will increase. D. i and ii E. all three 24. A solution is prepared by mixing 500. ml of 0.10 M NaOCl and 500. ml of 0.20 M HOCl. What is the ph of this solution? [K a (HOCl) = 3.2 " 10 8 ] A. 4.10 B. 7.00 C. 7.19 D. 7.49 E. 7.80 25. A 20.0-mL sample of 0.25 M HNO 3 is titrated with 0.15 M NaOH. What is the ph of the solution after 30.0 ml of NaOH have been added to the acid? A. 1.00 B. 1.05 C. 1.60 D. 2.00 E. 7.00

26. What is the minimum concentration of Cr 3+ that must be added to 0.095 M NaF in order to initiate a precipitate of chromium (III) fluoride. (K sp (CrF 3 )= 6.6 " 10 11.) A. 6.9 " 10 10 M B. 2.9 " 10 9 M C. 7.7 " 10 8 M D. 0.023 M E. 0.032 M 27. Which halogen is the strongest oxidizing agent. A. Cl 2 B. Br 2 C. F 2 D. I 2 E. None of the above are oxidizing agents. 28. How many coulombs (C) of electrical charge must pass through an electrolytic cell to reduce 0.44 mol Ca 2+ ion to calcium metal? A. 0.88 C B. 21,000 C C. 42,500 C D. 85,000 C E. 190,000 C 29. Which of the following ions could exist in either the highspin or low-spin state in an octahedral complex in the ground state? A. Sc 3+ B. Ni 2+ C. Mn 2+ D. Ti 4+ E. Zn 2+ 30. What is the [OH! ] of a solution made by mixing 25 ml of 0.1M NaOH with 45 ml of 0.02 M Mg(OH) 2? A. 0.049 M B. 0.061 M C. 0.076 M D. 0.14 M E. 0.17 M

Use the diagram and information below to answer the next two questions. A voltaic cell is constructed with two Zn 2+!Zn electrodes. The two cell compartments have [Zn 2+ ] = 1.00 M and [Zn 2+ ] = 1.00 " 10!2 M. Zn strip 1M Zn(NO3)2 left right 31. Which electrode is the anode of the cell and which direction does current flow? anode Direction of current A. left electrode Left to right B. right electrode Left to right C. left electrode Right to left D. right electrode Right to left E. neither Current does not flow. --------------------------------------------------------------- 32. What is the cell emf E cell? A. 0.059 V B. 0.12 V C. 0.76 V D.!0.12 V E.!0.76V 1" 10!2 M Zn(NO3)2 Zn strip 33. Two complex ions containing Ni were demonstrated in class: [Ni(H 2 O) 6 ] 2+, was green, and [Ni(en) 3 ] 2+, was purple. Which one of these statements is true? A. The crystal field splitting energy ($) is greater for [Ni(en) 3 ] 2+ than for [Ni(H 2 O) 6 ] 2+. B. [Ni(en) 3 ] 2+ absorbs energy in the red region of the spectrum. C. Both complex ions are diamagnetic. D. [Ni(H 2 O) 6 ] 2+ transmits light with wavelengths of approximately 650 700 nm. E. The green complex absorbs green light. 34. What is the value of the equilibrium constant for the following reaction? K sp = 3.0 " 10 16 for Zn(OH) 2, K f = 3.0 " 10 15 for Zn(OH) 4 2 A. 0.90 B. 1.1 Zn(OH) 2 (s) + 2 OH! (aq)!"zn(oh) 4 2 (aq) C. 1.0 " 10!31 D. 9.0 " 10 +30 E. 1.0 " 10 +31

35. The figure below is a plot of $G versus absolute temperature for a chemical process. Based on the plot, what can you conclude about the reaction? A. $H > 0, $S > 0 B. $H > 0, $S < 0 C. $H < 0, $S > 0 D. $H < 0, $S < 0 $G T(K) E. The reaction will be spontaneous at all temperatures. 36. The nitrosonium ion, NO +, forms a number of interesting complexes with nickel, cobalt, and iron. According to molecular orbital theory, which of the following statements about NO + is correct? A. NO + has a bond order of 1 and is paramagnetic. B. NO + has a bond order of 2 and is paramagnetic. C. NO + has a bond order of 2 and is diamagnetic. D. NO + has a bond order of 3 and is paramagnetic. E. NO + has a bond order of 3 and is diamagnetic. 0 37. What is the equilibrium constant for the reaction below at 25 o C? A! B A. 0.185 B. 0.522 C. 0.0154 D. 4.17 E. 64.9 $G f (A) = 8.066 kj/mol $G f (B)= 12.24 kj/mol? 38. Which one of these salts will form an acidic solution upon dissolving in water? A. i B. ii and iii C. i and ii D. ii and iv E. i and iv i. NaNO 2 ii. NH 4 NO 3 iii. KBr iv. AlCl 3 Go on to the last page

39. Predict the elemental products obtained from electrolysis of a 1 M AlBr 3 solution using inert Pt electrodes. Pertinent reduction half reactions are given. Half reaction E 2H 2 O(l) + 2e # H 2 (g) + 2OH (aq) 0.83 V O 2 (g) + 4H + (aq) + 4e # 2H 2 O(l) +1.23 V Br 2 (l) + 2e # 2Br (aq) +1.08 V Al 3+ (aq) + 3e # Al(s) 1.66 V A. Al and Br 2 B. Al and O 2 C. H 2 and O 2 D. H 2 and Br 2 E. Al and H 2 40. What is the rate of loss of [Br! ]!!!!"!! for the reaction!! below if!!!"!!!!!!!!!!!!!! at the same instant?!!! BrO 3 (aq) + 5Br (aq) + 6H + (aq) # 3Br 2 (!) + 3H 2 O(!) A. 13 M/s B. 7.5 " 10 2 M/s C. 1.5 " 10 2 M/s D. 3. 0 " 10 3 M/s E. 330 M/s End of Exam Form A 1. E 2. D 3. D 4. C 5. A 6. A 7. D 8. C 9. E 10. E 11. C 12. B 13. C 14. E 15. A 16. C 17. C 18. C 19. C 20. B Chem 112 Summer 2013 Final Exam Answer Key 6/24/13 21. D 22. E 23. E 24. C 25. D 26. C 27. C 28. D 29. C 30. B 31. D 32. A 33. A 34. A 35. A 36. E 37. A 38. D 39. D 40. B 41.