Practice Questios for Exam 3 C 1020 Sprig 2017 1. Which of the followig ca be cosidered a Brøsted-Lowry base? 5. What is the p of a solutio for which [Ba(O) 2 ] = 0.015 M? 6. The figure below shows three acids X, Y ad Z, (water molecules are omitted for clarity). Which acid has the largest pka? I II III A. I oly B. II oly C. III oly D. I ad II E. II ad III 2. Upo losig a proto, a Brøsted acid becomes A. highly reactive B. its cojugate base C. its cojugate acid D. a hydroium io E. a hydroxide io 3. Cosider 0.10 M solutios of the followig: NO 2, NaO, N 3 ad I. Oe of the solutios was foud to have a p of 11.12 ad aother solutio, a p of 1.67. What are the idetities of the two solutios? A. The solutio with p = 11.12 is NaO ad the solutio with p = 1.67 is I. B. The solutio with p = 11.12 is NaO ad the solutio with p = 1.67 is NO 2. C. The solutio with p = 11.12 is I ad the solutio with p = 1.67 is NaO. D. The solutio with p = 11.12 is N 3 ad the solutio with p = 1.67 is I. E. The solutio with p = 11.12 is N 3 ad the solutio with p = 1.67 is NO 2. 4. The ioizatio costat, K w, of water at 60 o C is 1.00 10 13. What is the p of pure water at this temperature? A. X B. Y C. Z D. it depeds o the amout of acid preset. 7. I this reactio the equilibrium favors reactats (lies to the left as writte). Which species is the strogest base? N + + O N A. N 3 + C. N 4 B. 2 O D. O 8. Calculate the hydroxide io cocetratio for a aqueous solutio that has a p of 3.45. 9. Which of the followig solutios will have the lowest p? A. 0.10 M CN (K a = 6.2 10 10 ) B. 0.10 M IO 3 (K a = 1.6 10 1 ) C. 0.10 M F (K a = 6.8 10 4 ) D. 0.10 M COO (K a = 1.8 10 5 ) E. 0.10 M NO 2 (K a = 7.1 10 4 ) O
C 1020 Sprig 2017 Practice Questios for Exam 3 Page 2 of 7 10. Which of the acids i questio 9 has the strogest cojugate base? A. CN D. COO B. IO 3 E. NO 2 C. F 11. A 0.10 M aqueous solutio of a acid has a p of 5.44. What is the value of K a for this acid? 12. What is the p of a solutio that cotais 0.033 M boric acid, 3 BO 3? The K a for boric acid is 5.4 10 10. 13. What is the p of a 0.050 M solutio of chloroacetic acid? For chloroacetic acid, K a = 1.4 10 3. 17. I a aqueous solutio which is 0.1 M sodium acetate, CO 2 Na, the cocetratio of hydroium ios [ 3 O + ] is. A. less tha the [ 3 O + ] i 0.1 M acetic acid. B. equal to the [ 3 O + ] i 0.1 M acetic acid. C. greater tha the [ 3 O + ] i 0.1 M acetic acid. D. impossible to compare with the [ 3 O + ] i 0.1 M acetic acid. 18. Classify each of the followig salt solutios as eutral, basic or acid. A. Na 2 CO 3 C. CaBr 2 B. N 4 Cl D. KNO 2 19. What is the p of a solutio prepared by mixig 40.0 ml of a 0.15 M solutio of F with 50.0 ml of a 0.20 M solutio of NaF? (The K a of F is 3.5 10 4.) 14. What is the percet dissociatio of a weak acid if its iitial cocetratio is 1.5 M ad its K a = 4.5 10 4? 15. Cosider a geeric polyprotic acid 2 YO 3. What is a appropriate combiatio of acid dissociatio costats for this acid? K a1 K a2 A. 2.1 10 4 8.9 10 5 B. 3.2 10 6 2.2 10 10 C. 4.5 10 10 6.7 10 6 D. 5.3 10 5 1.8 10 4 16. A aqueous solutio of which of the followig salts will give the most basic solutio? A. NaOCl C. NaClO 2 B. NaCl D. NaClO 3 20. Blood is buffered by the carboic acid/bicarboate buffer system ( 2 CO 3 /CO 3 ). If the p of the blood starts to rise (for example if your kideys fail to metabolize urea properly) which compoet of the buffer system will react to maitai the correct p? A. 2 O C. CO 3 2 B. CO 3 D. 2 CO 3 21. You have the followig bases ad wat to prepare a buffer solutio with p = 8.90. Which oe do you choose? A. ciolie K b = 2.3 10 12 B. pyridie K b = 1.7 10 9 C. ketamie K b = 3.0 10 7 D. codeie K b = 1.6 10 6 E. dibutylamie K b = 1.8 10 3 22. Give 100.0 ml of a buffer that is 0.50 M i OCl ad 0.40 M i NaOCl, what is the p after 10.0 ml of 1.0 M NaO has bee added? (K a for OCl = 3.5 10 8 ).
C 1020 Sprig 2017 Practice Questios for Exam 3 Page 3 of 7 23. What is the [ 3 O + ] cocetratio of a solutio formed by mixig 50.0 ml of 0.20 M Cl ad 50.0 ml of 0.10 M NaO? 24. Show below is a titratio curve for ascorbic acid (Vitami C). 27. ow may electros are trasferred i the balaced redox reactio for the electrochemical cell summarized below? Al(s) Al 3+ (aq) Cd 2+ (aq) Cd(s) 28. What is E for the galvaic cell represeted i questio 26? Ascorbic acid is a. A. strog acid B. strog base C. weak acid D. weak base 25. Based o the above titratio curve, what is the approximate pk a for ascorbic acid? A. 2.80 D. 4.10 B. 6.00 E. 8.70 C. 10.60 26. A 1.0 g sample of a ukow substace was titrated with a 0.1 M Cl solutio (Figure 1). Aother 1.0 g sample of it was titrated with a 0.1 M NaO solutio (Figure 2). Give the followig possibilities, what is the sample? Figure 1 Figure 2 29. Three metals, A, B, ad C, are immersed i solutios with their respective catios ad the tested i a galvaic cell with the followig results: A ad B: A is the cathode B ad C: C is the cathode A ad C: A is the aode What is the order of reductio potetials of the catios, from highest to lowest? highest E reductio lowest A. A > B > C B. C > B > A C. C > A > B D. B > A > C E. A > C > B F. B > C > A 30. Based o the cell iformatio below, determie the stadard reductio potetial for the followig reactio. M 2+ (aq) + 2e M(s) M(s) M 2+ (1 M) 2 + (1 M) 2 (1 atm) Pt(s) E cell = +1.18 V 31. Copper will spotaeously reduce which of the followig? A. Na 2 CO 3 B. NaCO 3 C. 2 CO 3 D. KO E. NO 2 A. Fe 2+ ad Ag + B. Fe 2+ C. Ag + D. Al 3+ E. Fe 2+ ad Al 3+
C 1020 Sprig 2017 Practice Questios for Exam 3 Page 4 of 7 32. For the galvaic cell pictured below, which statemet is true? 35. Which of the followig is true for the cell represeted here? Z(s) Z 2+ (aq) S 2+ (aq) S(s) A. The electros flow from the zic electrode to the ti electrode. B. The electros flow from the ti electrode to the zic electrode. C. The ti electrode is oxidized. D. The zic electrode is reduced. 36. What is ΔG for the reactio below? 2 AlI 3 (aq) 2 Al(s) + 3I 2 (s) A. Potassium ios from the salt bridge flow toward the Fe electrode as the electrode is oxidized. B. Potassium ios from the salt bridge flow toward the half-cell where Fe 3+ is reduced. C. Potassium ios from the salt bridge flow toward the Cr electrode as the electrode is oxidized. D. Potassium ios from the salt bridge flow toward the half-cell where Cr 3+ is reduced. 332 What is E for the galvaic cell depicted questio 31? 34. Which of the followig statemets is true for the galvaic cell depicted below? 37. What is E cell for the followig et ioic reactio if its equilibrium costat is 72? Ru 2+ (aq) + Tc(s) Ru(s) + Tc 2+ (aq) 38. Cosider the followig electrochemical cell. Cu(s) Cu 2+ (aq) Fe 3+ (aq), Fe 2+ (aq) Pt(s) Which actio will make E cell more positive? A. Icreasig [Fe 3+ ] B. Icreasig [Cu 2+ ] C. Icreasig [Fe 2+ ] D. Icreasig the mass of Cu(s). E. Both A ad D. F. Both B ad C. 39. What is the potetial at 25.0 C of the cell represeted below? Z(s) Z 2+ (aq, 0.010 M) Ag + (aq, 0.20 M) Ag(s) 40. Cosider the followig reactio at 25 C. Cu 2+ (aq) + Fe(s) Cu(s) + Fe 2+ (aq) A. The mass of the S electrode decreases durig the reactio. B. S is the cathode. C. The cocetratio of Cu 2+ icreases as the reactio proceeds. D. Cu 2+ is the aode. What is [Fe 2+ ] if [Cu 2+ ] = 0.040 M ad E cell = 0.76 V?
C 1020 Sprig 2017 Practice Questios for Exam 3 Page 5 of 7 41. For a electrolytic cell, which is the correct combiatio? E G A. + B. + + C. D. + 42. Idetify the family for each of the followig. A. C 2 O B. C 2 C 2 O C. CC 2 D. C 2 COO E. C 2 N 2 46. Which of the followig ames is correct? A. 1,2-dimethylhexae B. 2-ethyl-3-methyl-2-butaol C. 4-methyl-3-petee D. 3-ethyl-2-methylhexae E. 4-ethyl-2-methylpetae 47. Arrage the followig by icreasig vapor pressure? I. OC 2 C 2 C 2 O II. (C 2 ) 5 III. C 2 C 2 C 2 O IV. OC 2 C 2 V. C 2 C 2 C 2 N 2 43. To which family does the followig belog? 48. Arrage the followig by icreasig boilig poit. I. C 2 C 2 N 2 II. C 2 O III. C 2 C=C IV. C 2 C 2 V. C 2 C 2 O A. alkee B. aromatic C. alkye D. alcohol E. alkae 44. Provide the chemical formula for the followig. 49. Arrage the followig orgaic compouds by icreasig solubility i water. I. C 2 OC 2 II. C 2 C 2 C 2 III. C 2 C 2 C 2 O IV. C 2 CO 2 50. I which of the followig is hydroge bodig likely to be the most sigificat compoet of the total itermolecular forces? 45. Name the followig. A. C 4 B. C 5 11 O C. C 6 13 N 2 D. O E. CO 2
C 1020 Sprig 2017 Practice Questios for Exam 3 Page 6 of 7 51. Which of the followig are structural (costitutioal) isomers? 53. Which oe of the followig is NOT a structural isomer of octae? C C Structure I C 2 2C C 2 2C C 2 C2 Structure II A. B. C C 2 C 2 Structure III C C Structure IV C. A. Structures II ad IV B. Structures I ad III C. Structures I, II, III ad IV D. Structures I ad IV E. Structures II ad IV D. 52. Which of the followig compouds exhibits cis/tras isomerism? E. A. CCl=C C. CCl 2 =C 2 B. CCl=C 2 D. C 2 =C 54. Name the five compouds i the above questio.
USEFUL INFORMATION [base] p = pk a + log K a K b = Kw = 1.00 x 10 14 at 25 C [acid] G o = FE RT E = E l Q At 298 K: F 0.0257 E = E l Q 0.0591 E = E log Q RT E = l K At 298 K: F E = 0.0257 l K E = 0.0591 log K 1 V = 1 J/C 1 F = 96,500 C/mol e R = 8.314 J/K mol = 0.08206 L atm/ K mol Table 1. Stadard Reductio Potetials at 25 C Reductio alf Reactio Ag + (aq) + e - Ag(s) 0.80 V Fe 3+ (aq) + e - Fe 2+ (aq) 0.77 V I 2 (s) + 2e - 2I (aq) 0.54 V Cu + (aq) + e - Cu(s) 0.52 V Cu 2+ (aq) + 2e - Cu(s) 0.34 V 2 + (aq) + 2e - 2 (g) 0.00 Fe 3+ (aq) + 3e - Fe(s) 0.04 V S 2+ (aq) + 2e - S(s) 0.14 V Cd 2+ (aq) + 2e - Cd(s) 0.40 V Fe 2+ (aq) + 2e - Fe(s) 0.45 V Cr 3+ (aq) + 3e - Cr(s) 0.74 V Z 2+ (aq) + 2e - Z(s) 0.76 V Al 3+ (aq) + 3e - Al(s) 1.66 V E o