exam3sol - CHEMISTRY 204 Hour Exam 3 April 285 2010 Prof....

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Unformatted text preview: CHEMISTRY 204 Hour Exam 3 April 285 2010 Prof. Jim Lisy This exam contains 30 questions of equal value on ll numbered pages. Check now to make sure you have a complete exam. You have two hours to complete the exam” Determine the best answer to each question and circle your answer on the exalt/1.; Total (l 00 pts) Useful information, formulae, constants and a periodic chart of the elements are on the last two pages of the exam. You can remove them from the exam as you answer the questions. HERSJQME CHEMISTRY 204 Spring 2010 Hour Exam 3 Page No. l 1) Use the following graph of a second order reaction to answer the following question 90» 3 l M an v “a; 70 E 2? be é ‘33:: ‘30 " é we . l 30 u i in _ f i E i 0 " ‘ g o 5 1C) is : time€min) What is the value ofk? a) WS L moi min"1 b) 3 L/mol c) 9 L mol"1 (l) 9 L mol"1 mini} 5 L mol1 min"1 2) if an isotopically pure solution of thorinm~234 was prepared at a concentration of 50 g/L and the half life of 234Th is 241 days, what is thepconeentration of 234Th after 120 days? a) rig/L b) 3.2 g/L o) 2.9 g/L * d)“ 1.6 g/L -‘ e) 0.8 g/L _ 3) Which of the following statements is tine for an elementary reaction step or steps a) rate law can be written directly from the stoichiometry b); The rate laws are restricted to unimoleeular and himolecular reactions. c) The rate law can include concentration dependences that are integer or half-integer. d) The rate‘determining step is NOT an elementary reaction step. e) Termolecular elementary reactions steps are the most common of all elementary reaction steps. CHEMISTRY 204 Spring 2010 Hour Exam 3 Page No 2 4) The reaction 2N205(g) w>> 4 N02(g) + 02(g) has been studied at two temperatures and the following values ofk were obtained: Which value most accurater reflects the activation energy? a) 9.9 x 102 J/mol h) 1.2 x 103 J/moi c) 9.9 x 103 J/mol I’d) 1.0 x 104 J/mol 1.0 x 1053711101 5) A proposed mechanism for a reaction is C4H98r has C4H9+3+ Br" slow cat; + H20 cargorr; fast (:4H90H2"‘ + H20 W» c4rrgori + mot“ fast The rate law given by: a) Rate 1{[C4I{90}}ig+][HZO} to) Rate racirrgmrrzo] c), Rate :1<[c4r~rger][rr2o]2 a) L‘FRate :1{[C4H9}3r] e) Rate :: meager] [17120]"2 6) The activation energy for the reaction Now) + C0(g) we N0(g) -+ cows) is 125 kJ/mol, and the AEfor the reaction is "216 kJ/mol. What is the activation energy for the reverse reaction? ' a) 425 kJ/mol r b) 91 kJ/mol y 91 kJ/mol ‘ i “ {a}; 341kJ/m01 466 kJ/mol Cl-lEMlSTRY 204 Hour Exam 3 7) 9) a) 29s kJ/mol Nets) + One) «a Nozts) r We) a) 52.0 x 10‘25 L mol"1 s“1 1.1 x 1012 L moi"1 s] r) r d), Spring 2010 Page No. 3 The activation energy for a certain chemical reaction is 50.0 kJ/mol. In the presence of a catalyst at 37 0C3 the rate constant for the reaction increases by a factor of 2.5 x 1039 compared to the uncatalyzed reaction. Assuming that there is no change in the preexponential factora A9 calculate the for the catalyzed reaction a) 49.6 kl /1nol 4-7.6 kl/mol d) 20.2kJ/mol e) lOclkJ/mol Consider the following reaction that has a rate constant at 298 K. of 1.2 x 1010 L mol'1 s43 Given the following information (at 298 K): AGfO(NO) = 86.6 lad/incla AGfOCNOZ) = 51.3 I, , ,, kJ/mol, AGfO(O3) : l63.2 kJ/rnol, what isthe rate constant forthe reverse reaction? 1 x :’ , b) 1.: x 10 “12 Liner1 s01 c) 4n4xlO7Lm014 s"1 d) r5x108Lmor1s"1 Which of the following is an example of an electrophilic substitution reaction? When heating 2~butene and hydrogen gas in the presence of a platinum/carbon catalysta butane is formed '5“ f Using NOZ+ to react with benzene to form nitrobenzener Burning methane in an excess of oxygen makes carbon dioxide and water. ~~ - ~ In the first step of petroleum refinement a chromium oxidant is used to convert alkanes into more reactive allrenes. After leaving a saturated solution of sodium chloride undisturbed for two weeks, clear block crystals appear on the bottom of the container. - V" ’ 10) In a combustion analysis, 5.535 g of a hydrocarbon formed 6.75 0 g of water and 17550 g \ I» \l of carbon dioxide. What is the empirical formula thehydrocarbonl_,_> a) C4133 / if” / C6Hl6 C8H15 ’ I» H d) C10H22 {,5} j \ g 6) C12H30 x, CHEMISTRY 204 Spring 2010 Hour Exam 3 Page No. 4 11) Which of the following is cis~3Awdimcthyi-fi~hcxono? 12) Which of the following is not a possible product of the electrophilio addition reaction between 1,3«pcnmdieno and hydrochloric acid? " 4~ch10ro-2»—pontene 3 ~=ch10ro~1~penteno 3~chloi'o-2~pcntonc 5—ch101°om2~pcnteno _ 4wchloro-1wpcntcno _,__.a)?" i 2;-iodowélwcthylwéiammethylpcritch 3 53 ~dimcthyi~5 wiodohexaoc c)? 2wiodo~4,4“dimcthylhoxane iii) ‘72»cthylx~2~mcthy1w4wiodopentano _ u c)" 4wiodo~2-~(1 -:mothylothy1)pcntanc CHEMISTRY 204 Spring 2010 Hour Exam 3 Page No“ 5 14) Which of the following molecule is chiral? ii ,fi/j Q Use the following chemical structure of serine, a common amino acid. to answer the next two questions, l5 and lo, HO/\E [a 15) What is the name of the functional group marked A? a) Ketone b) Aldehyde Carboxylie acid Amide e) Alcohol 16) What is the name of the functional group marked B? a) Amide b) Alkene 0) EStei' Amine CHEMISTRY 2104 Spring 201 0 Hour Exam 3 Pago No 6 1.7)Wl1at is the name of the following compound? OH QM a) Zwmothyl»l,4-diol-pontanolo acid by) 1a4udihydroxym2~methylpetanono 4u~hydroxym2~methylpontanoic acid hydroxyl 4whydroxyw2«methylpontanone o) 2~hydroxy4~methyl~5«pontanoic acid 18) What is tho name of the following compound? (a) Ethyl propyl other Propyl ethyl othor o) lwe‘thylpropylothor cl) Propyl othanoato o) Pontanol CHEMISTRY 204 Spring 2010 Hour Exam 3 Page NO” 7 19)W11.at is tha structure of 2,5JiinethyL3 whefiénom? an '65" c) QOH d) f if y/ a 1 e) CHEMISTRY 204 Spring 2010 Hour Exam 3 Page No. 8 20) Which of the following monomars was used to make the foHOWing polymer? \/ C! a. b» Cl 1 / Ci C. C! ,6?" / d, Cl 6., CI CHEMISTRY 204 Spring 20l 0 Hour Exam 3 Page Not 9 21) What is the cell potential for a concentration cell formed by cormecting a 0.0010 M Zn2+/Zn half cell with a 0., 10 M Zn2+/Zn half cell? Reaction is at 25°C. Zn”r (aq) + 2 e‘ Zn (5) do v0.76 V a) “0.73 V {'Viyb)§_:}0.059 V 082; V d) 0.029 v c) 0079 V )5), 4, ‘ 22) A typical “heavy duty" Zincwchloride battery has a charge capacity of around 1500 mA-h (The units of 'Ampere hours' are easily converted to a total charge). Assuming the voltage is constant and high enough to drive the cell up until the battery runs out of charge, how many grams of silver metal could you produce with one AA battery from Ag"? a), 0056s ' V V V I {brieo g r yr ,r l . c) 56g d) 0.52g [ y L M 6) 4.8 g ,1, -, ; , \ 23) What statement below correctly defines the term "overpotential'fl in, regards to electrolytic cells? a) The potential of the combined. half cell reactions b) T he potential that must be applied to force an electrolytic reaction to proceed experimentally I c)“ The minimum potential required to thermodynamically drive an electrolytic cell d) "l‘ he additional potential difference required above the thermodynamically predicted value that is required to experimentally drive the formation of products e) The potential range over which a given electrolytic cell will operate 24) Determine the equilibrium constant for the reaction at 298 K: Cr (s) + Zn“ (aq) <—"> Crz+ (aq) “Ir Zn (s) Reduction Halllcell Potentials: Zn2+ (aq) + 2 e" ~> Zn (s) no 2 "0.76 V L\/ c134“ (aq) + 2 e“ w Cr (5) ‘0 m No.91 V a) 3.44x102 0 V __ b) i 1.68 ,_ w j " 1.39 x102 1.19xio5 e) 5.84 CllEMlS'l‘RY 204 Spring 2010 Hour Exam 3 Page No. l0 25) Calculate the ernf of the cell. Ag (8) l Agl (s) l r (aq, 0.050 M) H Fe“ (aqa 090 M) ; Fe (5) Reduction Half~cell Potentials: Agl(s) + e" «a» Ag (s) + l" (aq) E0 r: -~0.15 V Fe2+ + 2 e“ ~M> Fe (s) .30 :: 044 V v c) "40.25 V It d) +0.21 V _, e) +0.37 V “ 26) In order to remove lead ions from solution; an electrochemical cell is arranged with th+ (l M)/Pb (s) and H+ (l M) 03ng (l atin) l Pt(s) halfwcells. At room temperaturea 25 0C, which of the follow statements is true? a) One electron is transferred per mol of Hz b) The reaction will spontaneously plate lead onto the cathode c) The reaction will spontaneously produce H2 (g) at the anode potential must he applied to produce Ell" (aq) at the anode e) A potential. must be applied to plate lead onto the anode 27) Which of the following rate laws have an overall order of 3? CHEMIS’I‘RY 204 Spring 20 l. 0 Hour Exam 3 Page No. ll 28) Determine the order of the reaction with respect to each reactant from. the data in the following table» A2 + 483 + 6C e 2A(B4C2)3 ......................................... Experiment Rate = klAle[B3]‘[Clo 5:3)” Rate :2 k[A2]3[ngo[C]2 0)» Rate 2 k[A2]1[B3]O[C]'2 , p,c;:-*Rate = iclAzl4lle“1 [Cr Rate : k[A2]3[s3]0[Cr1 29) Which of the following plots produces a linear slope of Jr for the following first order reaction? R w» products a) ln[R]t vsi t "‘09)" l/llllR]tVS.l c) [RLvst d) l/[thst e) i/[sjztvm 30) Which one of the following statements is __false? The concentration of a catalyst may appear in the rate law equation, The half life of a first order reaction does not change as the reaction proceeds. c) iii‘nghe unique rate of reaction is the same for all species in a given reaction. regardless of ‘0 stoichiornetry. For a reaction with a very large equilibrium constant? the rate constant of the forward reaction is much larger than the rate constant of the reverse reaction. At equilibriurm the rates of the forward and reverse reaction are equal. CHER/1181183" 20/4- Spring 20110 11011113881111 3 Page NO. 12 1181:8111383 11‘ @1511 '11‘1118; 1851115817177118112118 2111118138“; MAW gym“ . u ’1 K“ d . > 8111 1111111138 7% 1 muting: .,55,88.;r’i """""""" 1 1 .. 2 H 111415.“: 1 = I Fr E9121 ‘ . 1 1.. 1881121811111381‘8 E11 iii-d 14:11 1152111585131 .15 . 1; ’ 1’ 1,4 9.6 81391153? , Pu Am $13131 f Bk . 1244112441,, 1-2421, 12421.1 1.18811 1 . 4» 80113111188 , 232113- : Additional 1701111111813 and constants: PanRT; 11 :1011'1‘ pH :- 4 1og10 [1130+]; 8,141,440 8125°C 11(8) :2 xappmg) 14.1 2:: [1130111434114] 41:»: 11:48 11b : [011*][181—11/[18] AT: ikbm KW: [mommy] 10”” 812,50C AG : AG°+RT 111 Q; AGO-2:- W111‘ 111 14: [1130+]:[0H14—[X]; [OHFH—hflj+[M'] AG = 41—1 _ TAS AC 2: 4171318; AGO : 4118110 dG :: 1/”de 881 13 :— 150 4 (111781?) mg Gm = Gmo + RT 1111) E r: w (0.0257/11) 1nQ 81298 14: 111 K. == u AHO/RT + ASO/R 811. 11111118 ~ PIGSSUIBLPaa Distancewm, Mass~kg, Time’s? 1311611;wa ForcewN R x 8.314 J 144111011: 8.314 m3 Pa, K481101714- 881411181421 K"1m01”1 Rn 8.206 x 10“2 L 211m 14:1 111011: 62.36 L 101‘1'1<_"1 mor‘ + 8.314 x 10"2 L “b81181”1 m01"1 F: 96490 C/mo]; 1 J = 1 V81 C; 1 A z: 1 C/s 1 atm = 1.01 x 105 Pa = 760 1011* PouStandard state pressure 1 bar = 105 Pa °»Sta,nda1°d state concentration 1 L I: 103 01113 0 °C 3273.15 K Standard Reduction Potentials and Kinetics 1.111081118181011 are 011 the 11681: page. CHEMISTRY 204 “(Hour Exam 3 Standard. Redumim Pastammfis: Aglaq) Cdz+(aq) +26" (3112+ (aq) +26" Fe + (aq) +26“ 2}; (aq) +26” 1112+(aq) +265 In (aq) +6“ Pb2"‘0(aq) +26" Sn2+(aq) +26" M> Ag(S); "‘r (361(8); w~> Cu(S); W7“ F603); w H205); m» 1:17am; ~—> 1:17am); w> PMS); W SIMS); Zn2+(aq) +26" M 211(3); Kinetics information E0: 0.80 V E0: 0.40 V B0: 0.34 V E0: «0.44 V B0: 0.00 V “0:: 0.44 V 40:: -~0.4~0 V 1": 0.76 V Spring 2010 Page No, 13 ...
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This note was uploaded on 11/19/2010 for the course CHEM 204 taught by Professor Gruebele during the Spring '08 term at University of Illinois, Urbana Champaign.

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exam3sol - CHEMISTRY 204 Hour Exam 3 April 285 2010 Prof....

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