225Sp07 Test 1 Key - CHEMISTRY 225 TEST #1 MAY 18, 2007...

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Unformatted text preview: CHEMISTRY 225 TEST #1 MAY 18, 2007 1-_,__... . ._.......(11) 2. (26) NAME V\ 9W 6. v 3- (14) PERIODIC TABLE or THE ELEMENTS 4. __ (12) B C N 0 F In.“ I101 mm 161‘] I94]?! l3 I4 11' - m a 5-———-——<‘2> 16.98 1!.” 15.4.1 E “ ’2 ca Sc; 1'1 V Cr Mn Fe Co Ni Cu 1n Ga Ge A: S: Br I108 «.96 a1.” 5094 am: 34.94 55.85 53.93 58.69 63.55 66.39 69.71 mm 16.9: rm 79.90 31' 3B 39 40 :11 ‘12 43 44 45 46 47 49 52 IE3 IS:r 381; FIZ'I! 91;] P! 3:19: [Elli Ilnllul 1% 36‘: IA I11. O [114"! lg: 1153 1.61 .I . . . . . . . . ’3 ” "° “ TOTAL “5) C5 30 La HI Ta W Re 0: Ir 1’! Au TI Pa [319 1313 “SJ {'13.} “1.0 I818 136.2 I901 191} 193.1 197.0 300. MA NU 199.0 {1091 [2'10] 8'? Es 39 104 [05 106 II];' 108 109 110 112 Fr Rn AI: R! Db S Bh H: M 11D] mu 111.0 liél) (261} I 1 m2] I355} [1%] {ml {in} 5 S 59 60 El 62 63 54 65 66 67 65 69 TD 7] Ce Pr Nd Pm Sm En Gd T'h I}; Ho Er Tm Yb Lu "DJ 110., I441 {HS} "0.4 I519 51.3 58.9 15 5 164.9 167.3 168.9 “19 "5.0 GOOD LUCK! 9'0 91 92 93 94 95 96 97 93 100 101 102 :03 Th Pu U N Pu Am Cm Cf Fm Md No L:- 111:1 um mo 23 .9 (:44) 4a » u um may as!) mum l. (l 1 Points) ORGO IN THE NEWS (POPULAR PRESS CATEGORY) a. ( f 6) As reported in the May 14, 200? issue of C'nemr'ccuT & Engineering News; Spectroscopic data obtained by the Cassinz' spacecraft have enabled scientists to identify organic substances in the atmosphere of Titan, the largest moon of Saturn. Among the species identified was a cation with the structure HCNH+. :- (2) Convert HCNH+ to a legitimate structural formula showing all bonds and lone pairs. The four atoms are arranged in the indicated order. 0 (2) Write a second resonance structure for HCNH+. o (2) Which of the two resonance structures is the more stable? Why? éivuz.luve. i'é- MAD-v! 94nLle; ’: 0 MCva (mucking-mi LIPMJL; 0 C!” ?u(‘ VUW (“Liam-‘5- 95Li.» (at!!! V“ (a 2 b. ( i 5) Unwanted organic compounds are turning up in all sorts of unexpected locations, including pet food and as components of “new car smell”. o (2) According to an article published in the Washington Post on May 7, melamine and NH2 cyanuric acid have been found in samples of J toxic pet food. The structure of melamine is N/ “EN shown to the right. Cyanuric acid (C3H3N3O3) has the same general cyclic structure as melamine except that hydroxyl groups replace all of the amino groups. Deduce the structure . . . cyanuric acid of cyanuric acld. i 13 in m 3. :5 CD 0 (3) According the New York Times, a “heady mix of aldehydes, ketones, and other volatile organic compounds” emanates from the dashboard of new cars. Researchers at the Technical University of Munich have concluded that these compounds might worsen allergies in people who have them. Write condensed structural formulas for a pair of isomeric carbonyl compounds, one an aldehyde and the other a ketone. The compounds must have at least five carbons. (9 t Git; CAI? (th at C/HC) on}, at, up; on; aldehyde ketone . (26 Points) STRUCTURE AND BONDING IN ORGANIC COMPOUNDS a. ( i 9) The highly functionalized molecule (compound A) below was used by Chinese chemists as a reactant for the synthesis of certain cyclic compounds {Tetrahedron Lett. 2007, 48, 3511]. o (8) Determine the geometry and hybridization at each of the indicated (arrows) atoms of compound A. NOTE: Lone pairs of electrons have been omitted from N and O. Geometry Hybridization ’ L LpH (D Ii -H== 1F ' '9 HZC=CH—CH—CH—CH2—OR _| -214 cm file“, 4, NH tip-00 cam Q; mi. (in! 98 J O NH - l l 9’42 '5 ' ‘2 aw : at. compoundA i I o (l) Directly on the structure of compound A, circle the ester group. 3 L b. ( f 4) Ethyl vinyl ether, structure to the right is an H\ (“H ___ bond 8 i example of an enol ether. It has two carbon-oxygen single bonds. ‘CZ'C / f \ k/'t} o (3) Use a hybridization explanation to account for the fact the H O_ _CH CH bond a is shorter than bond 6. 2 3 a aural Feud L: or»: K“‘~—-b0ndb 9'._ \L) lflOMJ Ct at?» .9L0«'l‘<v< 04. .H:- {larw-é‘Kl L7 0‘4!le Otis} with M I} L7,”; a“ C, pawl L. “work,” i .J ‘5 H 1. Wm m r L7 ml 4% cm a L L”! Witt. (lygalff‘:fr (ll-avoclif‘ fl; elutle (lineal; it» :iogcw ‘l-c, “TL: “Dylan; \_ i o (1) identify the orbitals that overlap to - _ .uf I . _\ ‘ C.zr: and '2“ l 0‘ 3" LL ' le‘ w form the pi bond of methyl vinyl ether. Lo A c. (___r’?) o (5) Sketch a picture of the sigma (0) bonds of propyne (CH3CECH). Be sure to identify the orbitals that overlap to form the sigma bonds. HINT: first determine the geometry at each carbon atom. - (2) Which of the following best describes the triple bond of propyne‘? (Circle one) three sigma bends two sigma bonds, one pi bond mwmm three pi bonds “ha-- ____________________________ __Hwflfls/ d. ( I 6) The resonance method - (3) Write two additional resonance structures for ethanoic acid, structure below. m ‘1' If 6;) s... ___ j E ‘ ’I Q 9/ l (,7 *——+ M,C (d; *——* #,a Q9 mg Cit; _ H CY /'\6—H H30 ethanoic acid - (3) Use the resonance method to compare the length of the indicated C—O bond to that of the C-0 bond of ethanol [CchHZOH]. Which bond would be longer? Defend your choice. ‘0 hav'fiel 'l‘r l’fludfui law Game-61 i9 C1 F” ya 5.} :1] it. La VJ. m C c O lac u-(i 3/! ("Ha—a vb}; ac '.cl/ 09 klww ct. l>7 W V-(L'Cwauce. we“...on L6H, “amt - . - ,e c Mel ('- a l— pie v ut‘l vi: 4»- at t L39' 1/8- vrer‘a—A cl a} Vcéo'v‘fil‘r'f'e- L7 L-i A? ‘llLaf Lemfll Outlet lI-LPCVEQQF“. l/c vhfll. lf njfllfi ('lwr‘veem-c r 4 3. (14 Points) STRUCTURAL FORMULAS AND ISOMERISM. 3’ (__.-.. -*’ 7) o (5) Writejogged Zine formulas for all compounds, C3H1g, with three methyl groups as the only branches. 7' ifxq __ T,. mffl?iF9\-’*r «4-5 C8H18 isomers I (2) Assign the MAC name to one of the structures you have drawn. Be sure to indicate which structure you are naming. b. ( f 7) Compounds from the chemical literature. 0 (3) Chemists at SUNY Buffalo have developed ‘ an enzymatic method that converts muconic acid to flavouoids, secondary plant metabolites used as nutraceuticals [Org Lett. 2007, 9, 1855]. Muconic acid, C6H604, is a straight—chain dicarboxylic acid in which all six carbons are hybridized spz. Write a condensed structural formula for muconic acid. Hora can: at as L—oa com muconic acid 0 (4) The dicarbonyl compound B, written in jagged line format below, was used as a reactant in a recent study by Japanese chemists [Org Lett. 2007, 9, 1859]. [ __. . '. O O compound B "‘H ‘ - Determine the molecular formula of compound B _g :L ’52, O z. - Circle the quaternary carbon; write in all tertiary hydro gens. c. ( f 3) BONUS QUESTION! Chemists at the University of Georgia have recently reported the results of theoretical calculations on unusual hydrocarbons [Org Lett. 2007, 9, 1851]. The simplest compounds studied had the molecular formula C4H6. Write the structure of the QR; isomer that has one sp3 hybridized carbon, two sp2 hybridized carbons, and one sp hybridized carbon. 4. (12 Points) FUNCTIONAL GROUPS a. ( __¥ K 9) Write condensed structurnlformulas for compounds satisfying each of the descriptions below. Your compounds must have at least four carbons. ‘oub all; CH~=CHL Lu; l gt. t . I. . .5 . fl = ._ . l EQiC/“e Met/ft CH 9‘20” U52. C H “L1 | on; or; or; cog l ‘ hilt amino acid terminal alkene alcohol . secondary alkyl halide CH3-- N: 5. (l 2 Points) MULTIPLE CHOICE. Write the letter ofthe correct response in the Space provided to the left of the question. There is only one correct answer per question. _ CI”; Which compound would be classified as an unsaturated hydrocarbon? A. Straight—chain alkane B. Branched alkane C. Alkyne D. Aldehyde _FD When atomic orbitals on different atoms overlap they combine to form a pair of molecular orbitals. Which statement concerning these molecular orbitals is TRUE? A. The molecular orbitals are formed as a bonding and antibonding pair. B. Antibonding molecular orbitals are always higher in energy than bonding molecular orbitals. C. ‘ Each molecular orbital can accommodate two electrons. D. A, B, and C are all true. Which of the following condensed structural formulas violates the rules of valence? A. CH3CH=CHCHQCH3 B. CH3CECCH2CH3 C. HCECCH=CHCH3 D. CH3CH2CH2CHZCH3 1:) Which two structures below represent the same compound? ‘le an as it as CH30H2CIZHCHCH20H20H3 Cl—{gCl-bCHCHQCHECHCHg CH3CH30HCH2(|3HCH3CH3 Cl—lgCHQCHZCHCHCHcha CH3 H CH3 CH5 I III IV A. land 11 B. 11 and III C. Ill and IV D. 1 and TV 6 C _ Deduce the identity ofthe molecular orbital to the right. A‘ 5})[Csp3 ' Cspj] BA fibWZp ‘ C213] C. 6*[C5p3 - C8133] D. rt*[C2p — C213] '\ i I _ __ Determine the number ofpi bonds in an acyclic compound with the molecular formula C4HgNQO. A. One B. Two C. Three D. Impossibleto determine from the information given. ...
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225Sp07 Test 1 Key - CHEMISTRY 225 TEST #1 MAY 18, 2007...

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