105bs10_w_sample4

105bs10_w_sample4 - Chemistry IOSbL First Letter of PLEASE...

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Unformatted text preview: Chemistry IOSbL First Letter of PLEASE PRINT YOUR NAME IN BLOCK LETTERS 11.00 am. Section Last Name Fall 2005 Name: EXAM #4 November 22, 2005 I Last 3 Digits SID #: Professor Arieh Warshel Lab T.A.'s Name: Lab Day and Time: Please Sign Below: I certify that I have observed all the rules of Academic Integrity while taking this examination. INSTRUCTIONS : 1. There are 5 problems on 9 pages in this exam. Please check to see that you have a complete exam. 2. Please show all of your work to receive fiill credit. 3. You must use ink. Do not use a pencil. Answers written in pencil are not eligibel for regrades. Useful Physical Constant: Avogadro's numb Universal gas cor ,t Faraday‘s constan‘ KP=KC(RT)A" w = €50?) ~ A Ifax2+bx+c=0 1cnx= PV-nRT -w‘q§ AS=k15 In W AG=-n1=g AG=AG° + 127‘an AG =AH ~TA' E=q+w AG” = -RT 1mm, ‘. Equations: N a 6.022 x 1021 mol" R " 0.08206 1.. atm K" me!" = 8.314 IK" mol" F = 96,485 C mol" -3 kB—N -b:l: blatac h .N Additional Infomation RT E=8°‘r|nQ <, 0.0592 e=e°- n 10gon 0.0 592 E°= n log“, K“ AGOd) = -96.5 n 2 (volt) eactions ' FLJJQ'W FOB) Cu" + 2c‘ -—r Cu(s) Zn‘2 + 2c“ -> Zn(s) Ni” + Ze‘ —) Ni(s) Mg" + 2c“ -+ Mg(s) Cd” + Ze‘ —) Cd(s) Sn+2 + ,2c' —9 Sn(s) ) I Q 8° volts -Q 11” 0.3 -0.76 -0.23 -l.03 o0.40 ~O.14 3 LI w H N. n__ on 7| I 20 : 2‘ 5 1 1 | ’ m I. ‘ C. h it 11‘ = u...“ flung" .3... a H. y. c. )1 n ) “JIM - , ‘1 lb , Y - A an» ’3 Cl nun-n I1 MM lA I. 5‘ 4A ,A u 1‘ 1 I) u u M H II 1020 Appendix C / Thermodynamic Quantities for Selected Substances at 298.15 K (ZS‘C) AH; AG; 5‘ ; AG; 5' Substance 1k] / mol) (k1 / mol) U/mol-K) Sub!!ch 01]] mol) {kl/mo!) 0/m01~ M Cob." ~ . Magnum 03(3) 439 393 179 Mug) 147-1 148.6 Co(s) o o 23.4 M318) 0 325' Mgcm) ~641.6 89.6 C0 , M306) -6o1.a . 26.8 CE?) 3384 166.3 1143101011) —924.7 . 63.24 Cu(s) 0 3330 CuCHs) - 205.9 108.1 Manglnese CuO(s) — 156 1 42.59 Mug) 280.7 01015) 92.36 MM!) 0 M1100) — 385.2 Fluonne MnO,(s) —Sl9.6 Hg) . Mno.‘(aq) — 541.4 :04) . M 1 ) a“!!! 111%) . 145(3) 60.83 143(1) 0 Hydrogen H8010) ' 80-1 Hm) “8202(1) “266-9 H'W) H' (3) Nickd 112(8) N11,) 429.7 0 Iodine - 3053 1(3) . I '09) 12(3) ‘19) HRS) Iron Fe(.1) Fess) Fe ‘(fln Fe"(aq) — FeCHs) — 203.0 94.6 NH.NO,(:) - 365.6 — 184.0 151 FeC1,(s) «no —334 142.3 NO(g) 9037 66.71 210.62 FeO(s) - 271.9 - 35.2 60.75 Fe,0,(s) - 82116 — 740.98 89.96 NO,(g) 33.84 51.84 240.45 Fe,0.(s) — 1117.1 -10142 146.4 N10(3) 81.6 103.59 220.0 Fes,(s) ~ 1715 —160.1 5292 19,043) 9.66 98.28 3043 NOCKg) 52.6 66.3 264 and mom) -206.6 «1105 146 Pb(s) o 0 68.85 W) — 1343 — 73.94 266.4 PbBrAs) ‘ 277.4 - 260.7 161 PbCO,(s) - 699.1 —65.5 131.0 Oxygen Pb(NO,),(aq) ~4213 —246.9 303.3 0(3) 247.5 230.1 161.0 Pb(NO.)2(s) - 451.9 - - 01(8) 0 0 205-0 PbO(S) - :17.3 —1a7.9 68.70 _ 03(3) 142.3 163.4 237.6 OH‘(nq) - 230.0 —157.3 - 10.7 Lithium Hm) ~241.32 —223.57 188.83 L113) 159.3 126.6 138.8 H,O(I) -285.83 —237.13 69.91 L1(s) 0 0 29.09 1110,13) — 136.10 —105.48 232,9 Li ‘(aq) ‘ 2785 ~ 273.4 112 H2010) -137.8 —120.4 109.6 1.1 '(g) 685.7 6485 133.0 L1C1(s) — 408.3 —384.0 5930 l. (20 points) 0) Using the data on the information page, indicate which is the anode in a cell based on the half cells of: Zn(s) -> Zn"(lM) + 2e- -O. 7; mad. M ,,; a . w _ o . Nl(s)-)NIZ(IM)+28 -023 5‘» M5 IS also determine the potential (3") for this cell. Fox/77V4v gum-+244”; 2%- +476 N; —-> MTV—2; —0.23 O M; ‘9 N£2++2¢— /fi ( A \\ / (0 ma: mic/2&5»; .- .- (ii) Based on the data on the information page, find the equilibrium constant at a for the reaction A $0,7‘ gang,” ~> C'oc -axw +0.34 = 5° AG”; -m F£°= ’RTAk M: 2 M o F: ¢Fr Zak: Mai-E R = P. 3/41 J’M'k' 7’= 278K Ak Jane :40 5;} k= 3 K: fits-KID 2’ "‘7 shun/M dam/MM 2. (20 points) (i) Please draw the electric cell formed by using 00001 M CdSO4 solution and a Cd(s) electrode and 0.2 M ZnSO‘ and a Zn(s) electrode. Determine what is the anode and what is the ca Qde Be sure to indicate all essential features of the cell so that current may (ii) Write down the anode and cathode reactions. a” - - _' 0.057 F) 14%: 13(3) 9514422- " 0'76 2, 2 Eli; \ €11.35- 2.7—) £1 = ‘a‘78 % Mats-[14¢ (iii) Indicate the direction of electron flow in the wire. ® g,“ 2.14 59%. ""0 04‘ 9”"- éi *4/71 VJ \. (iv) Calculate 2; for the cell at 25°C. .216 Zyaf. +Qe‘ +0,78 a“; 2e"—9G€ '45" K“ +0.2 6 V = (v) What concentration of Cal"2 will allow you to change the direction of thg current in the cell? 1 ""4 5" = 0 7t 0 . 2.4- a” ,a’ .4 E=O=E '00:”- CE’" J “77 all at! 2, Cu ‘ f] . k 3. (20 points) (a) Circle "True" or "False" for each of the following. (i) Cathode protection helps to keep a constant temperature in buffers. True (ii) F1 is a good reducing agent. True 1 / (iii) Biological systems use electrostatic processes to 3 ' perform their work. False (iv) When AG0 for an electric cell is zero, the emf must be zero. Tm- (b) Draw a battery and write the corresponding chemical reaction. M : an -> an "‘ + 2. “ 64W: Juli/If?" + QMnflz +0759 Mb") {'i ‘6! 0L “0” Mutt ” a GYM! MIL/9";— awed ahagfg M," 53,. (c) The potential of an electric cell is 2.00 V. LWhat is the maximum amount of work that can be performed by the cell? aid ){v ’3‘ "N’s ‘ hamsér OF WM“ :- ’ a. 2M“ ;A& '= 'M FEWK «(2.) W. “5907'” “Kl/3:) Wmflx “‘ no! WMM 4 ’ l 9 4. (20 points) (i) I?” 36603 x (ii) Fe- “ka'lf ‘9 Fe How many grams of Ni will be deposited on 21 met 1 Ampere current for 3000 seconds? {W :/ flea/ml» S‘ec lanai e")! q‘J‘JFC 2M8- al plate using electrolysis with Will the coverage of an iron plate by Sn prevent corrosion? Explain and quantify your result using the corresponding redox potentials. [.67 wII/ Sn rem}: 3+1£ A 7 S" ~> 3,.“ +2;- +0«/‘f :2? __A._J_o_. 52,4 Man‘ Aw firs/five 4V i+ 4. MM, M 44/25 Wynn“ 5. (20 points) (i) (a) What are the electronic configurations on Fe and Fe”? (b) Cr Fe. 4‘31 Jr! 6 Explain why the oxidation potential (M ~> M”'2 + 2e‘) of Mn is larger than that of Cr. (You must consider the corresponding change in electronic configuration.) H“ (/3131: "'9 [Ar] gals-18 anf [Av] 4.0345 —-> [MB/“M 0” DMn‘” is were $7616. 744“ Cr“" (fa/5' V3, z) Cr“ M 7% 1.5174141 (saw) 1/: M. (ii) (a) (b) (C) (d) Circle "True" or "False" for the following: EDTA is a polydentate ligand. False The d orbitals are being filled in the transition metal series. @ False The lead battery is used in standard calculators . Tme Electrolysis can be used to produce 1-12 from water. (Q False ...
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105bs10_w_sample4 - Chemistry IOSbL First Letter of PLEASE...

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