Name ID# Section # CH 1020 EXAM 3 Spring Form A

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1 Name ID# Sectio # CH 1020 EXAM 3 Sprig Form A Fill i your ame, ID#, ad sectio o this test booklet. Fill i ad bubble i your ame, ID# (bubble 0 for C ), ad sectio o the scatro form. For questio #60 mark A. Mark the best aswer after readig all possible choices. Use a #2 pecil ad make clea erasures to isure proper scorig. Whe fiished, tur i your scatro sheet ad show this booklet ad your CUID to the proctor. Questios are worth four poits. Good Luck! 1. Cosider the followig Brøsted-Lowery acid-base reactio which takes place i a o-aqueous solutio. NH 2 + HCN NH 3 + CN 4. The give four figures represet the dissociatio of four differet acids i water. Which of the acids is the weakest? Idetify the cojugate acid-base pair. A. NH 2 ad HCN B. NH 2 ad CN C. HCN ad NH 3 D. HCN ad CN E. NH 3 ad CN 2. The followig short-had otatio describes the electrochemical reactio occurrig i the galvaic cell show below. What letter i the diagram shows the locatio of the Fe(s). Fe(s) Fe 2+ (aq) O 2 (g) H + (aq), H 2 O(l) Pt(s) 5. Calculate the H 3 O + io cocetratio i a M Ca(OH) 2 aqueous solutio. A. B. aode E. cathode C. D. A M B M C M D M E M 3. Cosider the followig molecules, which is the least soluble i water? 6. What is the hybridizatio of each carbo atom (from left to right) i this compoud? A. C. B. D. A. sp, sp 3,sp 2 D. sp 2, sp 3,sp 2 B. sp, sp 2,sp 3 E. sp 2, sp 2,sp 3 C. sp 3, sp, sp 2 Page 1 of 4

7. A buffer is repeseted i the diagram immediately below. H 3 O +, OH, H 2 O ad spectator ios are omitted. 9. Determie the K a value for a 0.

04 10 4 Which of the ext diagrams best represets the buffer after the additio of a small amout of NaOH? 10. Which pair represets cis/tras isomers?

Give the pk a values for the followig acids, which acid has the strogest cojugated base? A. bezoic acid 4.19 B. chlorous acid 1.96 C. iodic acid 0.

2 7. A buffer is repeseted i the diagram immediately below. H 3 O +, OH, H 2 O ad spectator ios are omitted. 9. Determie the K a value for a M solutio of HCN(aq), give that the ph of the solutio is A B C D E Which of the ext diagrams best represets the buffer after the additio of a small amout of NaOH? 10. Which pair represets cis/tras isomers? A. D. B. E. C. 8. Which of the followig metals ca be used as the other electrode (M) for the give cell to be a galvaic cell? 11. Give the pk a values for the followig acids, which acid has the strogest cojugated base? A. bezoic acid 4.19 B. chlorous acid 1.96 C. iodic acid 0.77 D. acrylic acid 4.26 E. cyaic acid Which solutio will have the lowest ph? A M HCN D M H 2 CO 3 B M HNO 3 E M NaOH C M NaCl A. S C. Cu B. Fe D. Ni Page 2 of 4

3 13. Rak the followig compouds i order of icreasig boilig poits. 16. What are the mai three fuctioal groups preset i the molecule represeted below? lowest bp highest bp A. I < II < III B. I < III < II C. II < III < I D. II < I < III E. III < II < I 14. Which combiatio of solutios would give the titratio curve show below? A. ether, alkee, carboxylic acid B. alcohol, aromatic, carboxylic acid C. ether, aromatic, alcohol D. ether, aromatic, carboxylic acid E. ether, alkee, alcohol 17. A 0.10 M solutio of ascorbic acid has a ph of Based o the iformatio i the table below which statemet is correct for the relative stregth of ascorbic acid? acid % dissociatio 0.10 M citric acid 8.6% 0.10 M acetic acid 1.3% 0.10 M formic acid 4.2 % A. NaOH(aq) titrated with HCl(aq). B. NaOH(aq) titrated with HF(aq). C. NH 3 (aq) titrated with HCl(aq). D. HCl(aq) titrated with NH 3 (aq). E. HF(aq) titrated with NaOH(aq). A. Ascorbic acid is stroger tha citric ad formic acids but is weaker tha acetic acid. B. Ascorbic acid is weaker tha citric, acetic ad formic acids. C. Ascorbic acid is stroger tha acetic acid but weaker tha citric ad formic acids. D. Ascorbic acid is stroger tha citric acid but weaker tha formic ad acetic acids. E. Ascorbic acid is stroger tha citric, acetic ad formic acids. 15. Give the followig cell, V 2+ (aq) V 3+ (aq) S 2+ (aq) S (s) What is the balaced overall (et) cell reactio? Hit: Read the aswer choices carefully. A. V 2+ (aq) + S 2+ (aq) V 3+ (aq) + S(s) B. 2V 3+ (aq) + S (s) 2V 2+ (aq) + S 2+ (aq) C. V 2+ (aq) + S (s) V 2+ (aq) + S 2+ (aq) D. 2V 3+ (aq) + S 2+ (aq) 2V 2+ (aq) + S(s) E. 2V 2+ (aq) + S 2+ (aq) 2V 3+ (aq) + S(s) 18. I the balaced equatio below, which substace is the reducig aget? Which elemet is oxidized? Fe 2 S 3 (aq) + 12HNO 3 (aq) 2Fe(NO 3 ) 3 (aq) + 3S(s) + 6NO 2 (g) + 6H 2 O(l) reducig aget elemet oxidized A. HNO 3 N B. Fe 2 S 3 Fe C. HNO 3 S D. Fe 2 S 3 S E. HNO 3 Fe Page 3 of 4

4 19. Cosider the followig three salts: CH 3 CO 2 Na, NaHSO 4, ad NaNO 3. Which is/are eutral? A. CH 3 CO 2 Na oly B. CH 3 CO 2 Na ad NaNO 3 C. NaHSO 4 oly D. NaHSO 4 ad NaNO 3 E. NaNO 3 oly 23. A galvaic cell is costructed with the overall reactio: S 2+ (aq) + 2Ag + (aq) S 4+ (aq) + 2Ag(s) Which chage will icrease the cell voltage? A. icrease [S 2+ ] B. decrease [Ag + ] C. icrease [S 4+ ] D. reduce the size of Ag electrode 20. What is E for a galvaic cell based o this reactio below if ΔG is 799 kj? 2Al(s) + 3Co 2+ (aq) 2Al 3+ (aq) + 3Co(s) A V B V C V D V 21. What is the chemical formula for the followig molecule? 24. A buffer is formed that is M i CH 3 CO 2 H ad M CH 3 CO 2 Na. What is the ph of 1.00 L of the buffer after the additio whe moles of HCl is added? The Ka for acetic acid is M. A B C D E What is the cell potetial at 5 C of the galvaic cell represeted below? Z(s) Z 2+ ( M) Ag + ( M) Ag(s) A. C 5 H 12 D. C 7 H 12 B. C 5 H 11 E. C 7 H 11 C. C 5 H 10 A V D V B V E V C V 22. A solutio of hydrazoic acid, HN 3, has a ph of The additio of sodium azide, NaN 3, its cojugate base salt, will cause A. the solutio ph to icrease as more of the HN 3 will ioize. B. the solutio ph to icrease as the ioizatio of the HN 3 will be ihibited. C. o chage i solutio ph. D. the solutio ph to decrease as more of the HN 3 will ioize. E. the solutio ph to decrease as the ioizatio of HN 3 will be ihibited. 26. Pure water at ay temperature has: A. a ph less tha 7 B. a poh more tha 7 C. [H 3 O + ] = [OH ] D. ph = 7 E. o H 3 O + ios. 60. Mark Aswer A. Page 4 of 4

USEFUL INFORMATION G = G o + RT l Q G o = RT l K 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.

5 USEFUL INFORMATION G = G o + RT l Q G o = RT l K G o = FE RT E = E l Q At 298 K: F E = E l Q E = E log Q RT E = l K At 298 K: F E = l K E = log K [base] ph = pk a + log K a K b = Kw = at 25 C [acid] 1 V = 1 J/C 1 F = 96,500 C/mol e R = J/K mol = L atm/ K mol

6 Table 1. Stadard Reductio Potetials at 25 C Reductio Half Reactio Ag + (aq) + e - Ag(s) 0.80 V Cu 2+ (aq) + 2e - Cu(s) 0.34 V S 4+ (aq) + 2e - S 2+ (aq) 0.15 V 2H + (aq) + 2e - H 2 (g) 0.00 V Pb 2+ (aq) + 2e - Pb(s) 0.13 V S 2+ (aq) + 2e - S(s) 0.14 V V 3+ (aq) + e - V 2+ (aq) 0.26 V Ni 2+ (aq) + 2e - Ni(s) 0.26 V Fe 2+ (aq) + 2e - Fe(s) 0.45 V Z 2+ (aq) + 2e - Z(s) 0.76 V E o

Practice Questions for Exam 3 CH 1020 Spring 2017

Practice Questions for Exam 3 CH 1020 Spring 2017 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