Chemistry 3A - Spring 2001 - Frechet - Midterm 1

Chemistry 3A - Spring 2001 - Frechet - Midterm 1 -...

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Unformatted text preview: Chemistry 3A - Spring 2001 Midterm 1 Professor Jean Frechet You _t-- 1H,! :. In a I ._ _ February 2o.2co1 Frir 5... ......._-. ‘ _. ,. __t H You Please check the section number and name of your UIJHIH. _'1i:‘.1 Padilla-De Jesusflmavra _3T1 _l'r“l Foxflanlel _311 ___1Bl Furuta.F'aul _321 __191 Lingfrank ._451 _'I ‘t 1 Cordaro..Joseph £4fl _121 Le.Scheherazade _41‘1 _131 Thaiji,Reema _421 ___14‘t Catherine Sealay ___431 ___2i51 Peterkaflarov F551 __2?1 Miljanicflgnjen _511 __21‘l Derlz.Emilv _521 #221 Simon.Matthew ___361 Barry, David If vou are making up an I—grade. indicate the semester you took 3A FJ rofess or This exam has 1!] pagEs; make sure that you have them all. Please be sure to use the veg: useful data given on page 10. We will onlv grade answers that are in the designated spaces. Please do your scratch work on the backs of the exam pages. Write onlv gge answer to each problem; multiple answers will receive 93 credit. even if one of them is correct. m This examination runs for a total of Ell] minutes. No questions will be answered by proctors after the exam begins. Please write legiblv; ambiguous or messv answers will receive no credit. @2001 J_M.J. Frechet. Berkeley, CF. Miljanicflgnjen SivamaniRaja Li. Ben Huangfllan Liang.Catherine Phillipsficott SaxonEliana Dstarhout.Robin MerolleMauro KIopp.John Wufiarah _53'l RaoMikas and the Dr Chem. 3A - Midterm Exam #1 Page 2 of ti} 1. [ 1|] points] Name pr draw. as appropriate, the fallpw'rng mpEeeutee. “file (use IUF'AC rules of nemenptature) (use IUPAC rulee pf npmenelature} p. Cfe—t—butytud-methyleyelphexane {Meet stable conformatipn use the template provided} :1. Trans—1—pyplpprppyl-2-methy1cyplppentane a 7’,?—diehiprp-Z-methylepirp{5.2]petane Chem. 33% Midterm Exam #1 Page 3 of 10 2- I: 1‘5 Paints} (3‘;me the twn chair confcrmaticns of trans-1,4-dimethylcyctuhexane, 3;. ' :LT'lr {EH-i L'sifi; ki’k-fi/WD L = 315 it Ltd. /’m«~ cf. {DJ | Midterm Exam #1 Page 4 of 1D Chem. 3A 3. I: 12 points} 3b Draw a Newman projection of the | GAUCHE conformation of butane 64H“. I seen along the {32-63 bond. 3a. Draw a sawhorse projection of the least stable conformation of hexane CHflCthCHg as seen along the (3343.; bond . .w s: ca. 2 r the combustion of propane CSHE and calculate how much =12.H=1.D=1Ei. 3b. Write a balanced chemical equation to carbon dioxide is produced by the combustion of 44gl'afl'l5 of propane {use C Weight of carbon 5 .r"f'_~_,_‘_;s :1? (3a dioxide produced ' “ us chemist with the following {choose amongst: Grignard. Lewis. 3c. Match the name of a lame als. Pauling. Newman. Pauli. Shrodinger}. Helrule. Bohr. Planck. Einstein. Pasteur. yan der Wa ti} "No orbital may be occupied by more than two electrons" {iii The concept of intermolecular attractive forces Chem. 3A Midterm Exam #1 Page 5 of 1D 4. i 13 points} [i] Which of the following is the stronger acid [a] water or [b] ammonia? ,r" i {ii} 2.4-pentanedione {pKa = 9} is a stronger acid than 2—propanone {pKa = 22}. Note that in each structure below the proton involved in acid base chemistry is highlighted. Write the structure for the conjugate base of each acid and consider possible resonance forms1 then explain Why 214-pentanedione is more acidic than 2 propanone. fifi'iijLL'irfL'tL bfliii- £15 cow-«r. rc- iii} Write the electronic configuration and show the orbital energy diagram for Avigfir-rau cc fist-u; Chem. 3A Midterm Exam #1 Page 5 of it] 5. l ‘12 points}. {a} Name the scientist who introduced the following concept: "Bonds are made by the tit-phase ovarian of atomic orbitals ". to} Write the Lewisuoot structure for nitrogen N2 and for nitric acid HND; {HUNozl - {Show charges if any}. {c} What is the shape and approximate H-C-C bond angle for the molecule of ethyne CEHE? Draw it / in Kekule form and explain your answer using VSEFR. l—l ~ r; -—- or H T [Lit i-1-1 L'ACLLL L3 r 5:: Urn t m. :31. H ' (- " (- ELirfid t'S, JUI'“‘i—t_‘ti‘_.l~._r.,e[ to '3, +-tt iii-JESS: rt. m get-«1 rt. tie rhn L: ..-.l.‘-k.'.| final i i ELLE— Pth r, .t l-"t v“ E F.- P I94 r 44mi- ~‘—~ tr“— L‘J D LLUL b5— +fl $13“ MC. no. i'itLtTLQ 1 LL; 1'” Vt!“ 1" fl :1 d} 54"“ {await—L oi? Intro? firm-me we. o4 “E'txficda'fl— “H‘LLWKS LIE” l {a} What doest e abbreviation VSEPR stand for? —-:, 5L [em-L t r 1 ‘ ll ilk on“ Sr"; :1. run-:th _ _ I J; rah. Let H. I L _r __ ___ E_ 1',“ 1,: 1' _b.. a .1. HI 1.41- J y'ch M ELLE—Mn Paulo Espet'sr‘an fr. -- 3} L, a: to; learn? | lei Using arrowsr show which atoms of the molecule of trimethylamine oxide have a L'E: lot 4.; l I ; formal charge. Specify the formal charge by writing it clearly {e.g.:+3} next to the arrow [I , mi 5.“ __ | 5 # if at (q “pi-1L); Eng. | r 9' L! k { {‘_ if. 1"- "; ._"'I._.-:.",L D I\“'\~I / JP, ! I WLLJH lad-{Li ti. w” Lfif‘l L- I '5 Hui .' HBO—N—GHE 1 _I _ _ a r. ' k..- h'J { CH3 I Chem. 3A Midterm Exam #1 Page ? of 10 E. i 14 points} {a} llNhat is the hybridization of G in ethene C2H4. Draw the orbitals involved in bonding the two C atoms to each other. Label these orbitals showing their type {e.g. s or sp. eto_.}. ' what types of bends are formed between the mofarbons and indicate their type with a Cue ter. -; I - '~ r - ‘ '- --'...'” ri"C.=1CRfi4 .I fill—J,” "- -I.'._I| -3 o¢qflas *4 gzgpa %' 3i: flViii/ULP 0% anhuxhyn afi arm?1i Io Eb [oi Arrange the foilowing alkanes in order of increasing boiling points. i1}2-methyit}utane [ 2] propane {3} periteoe_ 2,2-dimethyipropane Chem. 3A a- H Midterm Exam #1 Page 8 of 1t] 1*. i 11 Pointslt'i {a} In 1,2-dichloroethane at room temperature, the ratio of molecules in the ANTl to GAUCHE conformation is "LE to 1. Calculate the difference in energy.»r between these two conformations. Show equations and detailed calculations. '_‘\. (Bent Mu. .§__-‘p 5Ly._vh' C I * .- Cfl-tl’fll _ ‘7_ cc aw fluf/ET Lari a [Easting] - 1 a: e” ("a _. ___. _: L f U J st in {at {a 3‘ El- -- i l-‘E{_+1_L COD :—R'T Lin (UL : ’ mgfiLj(Qei3olarh‘j Lin it, x [000%.]; .f— EMA/MEL {b} Calculate the equilibrium constant for the reaction below. CH3CDDH + NH3 —“—*‘ CchDD' + NH; Show detailed equations 3: calculations. hr—-- ,7: E" '4 IT '55 chlco 'JEHEIEF] Kai: [cuacuuH-g {His} Kt: Lie-fl: “t Km fi____;__———-———_—__—__.=_——_—___—————— ~I Chem. 3A Midterm Exam #1 Page 9 of ‘10 3- [12 Paints] {a} The monflbrominajgn of propane affords one major product. Write the propagation steps for the preparation of the major product and caicuiate aH” for the overall reaction. CHECLibQL-i; + ($1; —‘3(‘_H!CH$CH;Br + HIE-r aremémm mariacmws +113!”- —a~ cnficehflr-i; + H Fir: r._ Karachi, bani-Lint CHEEFLCH; "i—i 4.5 lLUgE/WDL {Ewes mesa: [at—Br 3%. amgmuL he" ' F" . _‘ a H o 1 b ,3 fl fji 5 19 p1:- Fifi fl F L: DH_&1IS Whfixfii—L‘ Juan :- Ilwf. iLi'iL-‘l/WaC-L “ :flLM/i-V‘ILPL: 7 Paropcefia’h'aw filifiL-llflt-Jéfli-Jl' + i313 —*:QIALCHECH&Er-i :iitf" E‘Ofiifi leaflet-aim: Er " igr' Lia's, ELM/Moi r‘rarS-ch; ICL-igaHéCL'ZfiE-r ELM/EWIGL I?) LEW-'51 5 3:. aw .- at. area muL nee lcaai/ \ +1- .. w-tflti‘; DHo Dflm’d: 1| Lead/moL-J; Hamil/moi a m for the formeton ot the major monooromination product of [hi Draw and iabei tne energyr diagra propane. CHEL‘LH‘CFLEK 4 Mar {swag-risi- gé' r-a a: 'H.) m Chem. 39. Midterm Exam #1 Pege1fl ef 1D e. it enly eentains date that may Mete: There are he questiena te lee answered en this peg is needed. he at use in seltting the guestiens eenteined in this exam. Net all at the data giiien cita efCH3CDDH = are Value ef gas eenstent: R = 2.12) eel deg'1 rnel'1 9K3 : lit'elne of e these fer rieturel logarithms] e = 2.213 Value at ehselute zere iltelitiri} = -2?3°C aonci disseeietien energies {in ttcat moic"): RCHz—H sit R2CH-H as eeHEaei 31 R3: _ Br Rail-H 91'. CIFC'I 58: BrwBr 45'. H-Elr BE: HHCI 1GB REHz-Er EB RECH—Cl Bl] FRESH-Er EB RgC-CI T9; Values ef strain energies: Eeeh CHa— i-l eellpsing intereetien: 1.5 keel rnel'1 Eeeh H - H eeliesing intereetien'. 'l.[l keel meld Eeeh CH3— CH3 eeiipsing intereetien: 2.5 keel i'iiel'1 Eeeh CH3 - CH3 butane-gauche intereetien: {1.9 keel ntel‘1 Eeeh t—Etutyl a CH3 gauehe intereetien: 2.12} iteel riiel'1 Each CH3- H 1,3-diexial intcraction: tie itcai moi'1 Eeeh CI a H 1.3rdiexiel intereetien: [1.25 keel rriel'1 Eeeh ei-i3 — eh3 i13-diexiel intereetien: 1.5 lteal nioi'1 Eeeh H - CM 1.3—dlexial intereetieri -. e.i itcai rnoi‘1 Eeeh H - C(CH3}3 1.3-diexiel intaraction: 2s itcai rnoi'1 Partial eriedle table ef the elements 2 IIIA WA VA VIA. ‘lt'llifll. tumfii‘i 5 E "i' E ' 9 10 B C N O F Ne 1'13“ i2..|:|‘|1 “£55? iiififid 15.2934 211.1?9? 13 14_ 15 15 1? 13 Al SI P 3 Cl Ar IE IIE 25.5215 23.0355 SHANE 32.055 35.452? 35.9w 29 3D 31 32 33 34 35 35 Cu Zn Ge Ge As Se Br Kr 53.515 55.35 53.213 22.51 24.5215 “.95 29.504 20 Ce team ...
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Chemistry 3A - Spring 2001 - Frechet - Midterm 1 -...

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