Exam1+key - Chemistry 23 11 Spring, 2009 Exam 1- Chapters 1...

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Unformatted text preview: Chemistry 23 11 Spring, 2009 Exam 1- Chapters 1 and 2 Part 1: Circle the number that corresponds to the answer to each multiple choice question. There is only one correct answer for each question. [20 points) 2, yrs M (1] een which of the following two atoms will a covalent bond be formed? and 0 [2) Li and F [3] Mg and Cl [4) K and Br (2] Which o e following bonds has the greatest bond moment? (1] C-C —F (3) C-H (4) C-N [3) Which of the follow' atoms is the most electropositive? (1) F (2) N (3) c 6: [4] Which o e following ions possess the electron configuration of a noble "inert" as? [1) Br+1 *1 (3) Ca+1 [4) S‘1 [5] Which of the following molecules will have the greatest dipole moment? F 0 CF F30 H 3 \ / 3 \ _ / / \ / \ _ . H H H CF3 (3) Fsc—c=c—CF3 F3C CF3 \ _ / (4) 0—0 / \ F30 CF3 (6] Which of the following statements is n_ot true of resonance structures? [1] The positions of nuclei in resonance structures must be the same. 2 The placement of the pertinent electrons in resonance structures is different. @Each resonance structure represents a real molecule that can be isolated. (4] The actual molecule will be more stable than any single resonance structure. [7] Which mic orbitals overlap to form the double bond of ethylene (CH2=CH2]? p2+sp2andp+p s + s and p + p (3)5103 + 5p2 and s + s (4)Sp+spandp+p [8) Which of the following is an incorrect Lewis structure? (1) :C:::o: .. n; @ HzozczozH :6: (3) :o::N:6:H (4) INIIINIQZ (9] Which of the following structures is a tertiagg amine? CH3 CH3 Q l (2) | H3C_N—CH3 H (I3H3 (3) (4) _ __ H30—N—H H30 (I; NH2 CH3 (10] Which ofthe following molecules has the highest boiling point? H C CH 3 \ — / 3 M @ /c=c\ H CHQOH H COZH H c CH (3) 3 \c=c/ 3 HBC\c= /CH3 / \ (4) / \ H COZCH3 H COCH3 Part II: Indicate True [T] or False [F] for each of the following statements. [20 points) 1 PYS M f (1) A dipole moment is a vector; it has magnitude and direction. 7(2) Different compounds that have the same molecular formula but different structures are called isomers. F (3) The formal charge on nitrogen of nitrate anion (N03'] is -1. F (4] Benzene is an equilibrium mixture of two constitutional isomers. ("[5] Polarizability is a measure of ease of response of electfbns in an atom or molecule to a change in electric field. 1’ [6) An atomic orbital is a region of space where there is a 90-95% probability of finding an electron. ((7) When atomic orbitals combine to form molecular orbitals, the number of molecular orbitals that results always equals the number of atomic orbitals that combine. ’f[8) The shape of ammonia [NH3] is trigonal pyramidal. ((9) Dipole-dipole forces are stronger the ion-ion forces. 7110] A hydrogen bond is formed by hydrogen acting as a bridge between two highly electronegative elements. Part 11!: Write or draw the answer[s] for each of the following questions in the space provided. (44 points] ' /L W QM (1) Draw a constitutional isomer of 2-chloro-cis—2-butene. 14 H CI H" 77% H30‘ 0: H3 M Cl [2) Draw a stereoisomer of 2-chloro-cis-2-butene. Cfl 1+ 3 . WC [3) There are seven constitutional isomers with the molecular formula C4H100- four alcohols and three ethers. Draw the dash formula representations for the three [4] Draw a valid Lewis structure for the nitrite ion: N02: What is the formal charge associated with each atom? What is the shape of the molecule? Draw the shape. W Lewis Structure and Charges Shape (5) The amide function is an important structural unit in peptides and proteins. Formamide, represented by the Lewis structure shown, is the simplest amide. It is a planar molecule with a dipole moment of 3.7 D. Lewis structures I-IV represent species that bear some relationship to the Lewis structure for formamide. D 53/" :B/H :520 :6? JL H i i i i H E/ H 35/” H \Nl H \N : H \N/H l I I i |‘*’ H H H H Formamide l I] [I] IV [1] Which Lewis foriula is a resonance contributor to the structure of formamide? [AJI (3)11 (@111 v [2)W ' h Lewis formula is a constitutional isomer of formamide? [A)I u [C] III (D) N (6] The resonance contributing structures for diazomethane are shown as follows: Q o (:3. a) a. .. .. (+3 “8 HQC—N:N Z HEC—N—N 2 HBCENKN I A C “fit/(e (1] For each of the resonance structures label the formal charges on each atom. (2) Which structure contributes least to the overall stability of the molecule? Q [7] Draw the Lewis representation of nitrobenzene and one resonance form. [8] Identify all of the indicated functional groups in the following compound. [9] Consider the following structure. Designate the hybridization for each of the carbon atoms indicated by the arrows. 6‘7 3 CH3 0 O /C C / \d 1. / (7? H OH ‘3? Part IV. IR Spectroscopy. Which of the following compounds is consistent with each of the following IR specra? [15 points) ‘3 F’tfi 0M (1) O OH (I) (2) (3) (4) lDI) TIINSHEFTH'NEEIII an a ll IIDO 3000 RUDD l 5 If! WW I I0 )IWEIUHIER I -II [2] [DO runsmrrnmctrz: a "00 (1) 3000 emu (2) REVENUHBERH! ISM N(CH3)2 1000 EEO Inn Tllnsnrrmrtsam El lllCID 3000 EDGE 7 15m: 1000 Elm Ilfl'l‘EflU-Hl EHI -|I A. Alkyl (3—H (stretching) 2853~2962 (m we) isopropyl, —CH(CH3)2 "1380w1385 (s) and 1365 ~ 1 370 (s) tert—Butyi, ~C(CH333 “E385 «w 1 395 (m) and m 1365 (e) E3. Alkenyl C-H (stretching) 3010—8095 (m) CmC (stretching) ' 1620—» 1680 (v) R—CHmCH2 _ 985 n 1000 (3) (Gut-Of‘p‘a”? and 905-620 (s) Rec-£0142 0—” bendms) 880—900 (s) ciefiCHwCHR 675 730 (s) trans—RCHmCHR 960 £975 (3) C. Alkynyi ECWH (stretching) ~ 3300 (a) CEO (stretching) 2100- 2280 (v) D. Aromatic ArmH (stretching) ~ 3030 (v) Aromatic substitution type (CWH out—ofvpiene bendings) Manoeubet-ituted 690 - 710 (very s) dDisubsEituted and 730— 770 (very s) WWI-substituted 735M770 (s) 680n725 (s) and 750-810 (very s) p—Disubstituted 8004560 (very s) E. Alcohuls, Phenols, and Carboxylic Acids OWH (stretching) Alcoheis, phenols (diiute solutions) 8590m3650 (sharp, v) Alcohois, phenols (hydrogen bonded) 32(30n3550 (broad, s) Cerboxyiic acids (hydrogen bonded) 2500~3000 (broad. v) F. Aldehydes, Ketones, Esters, and Carboxyfic Acids CmO (stretching) 16304780 (5) Aldehydee 1690— “1740 (s) Ketones ‘i 680-— 1750 (s) Esiers 1735M ? 750 (s) Carboxy‘lic acids 1710~ 1 780 (s) Amidee 1630w‘1690 (e) G. Amines N—H 3800+3500 (m) H. Nitriies 2220»~ $2260 I 1'92" 4-333: “Abbreviations: s strong. m medium, w weak. v m variame. w approximateiy. Periodic Table of the Elements I 2 H ‘ H He 1.00794 I ,00794 4.002602 . ’ 9 F .. $398403. 20.]797 . f4 I5 16 I7 1 Na Mg S1 P 8 C1 A 22.989770 24.3050 25.981533 28.0855 30.97376] 37.. 66 35.452? 39.946 . .2 39 4| S 40 42 43 46 4s 49 so 1 Y Zr Nb M0 Tc Pd Ag Cd Sn Sb 1mm 83.90585 9|.214 92.90638 95,94 (93) 106.42 107.3682 “2.4M 118.710 121.760 57 73 74 78 79 80 8} 82 . La Ta W Pt Au Hg Tl Pb Bl i38.9055 $0.947“) 183.54 195.078 19636655 200. 9 204.3333 207.2 .20838038 (205)) (110) i 1} H4 8 r 0 . 22 2] 24 25 27 18 29 30 3] 1 33 34 .. 6 T1 Cr Mn - C0 N1 Cu Zn Ga Ge - Se r 47.307 50-9415 “.9963 54.938049 . . 53.93.1200 58.6934 63.546 65.39 69.723 72.01 74.92160 78.96 , 47 5 - ‘ I16 (239) 69 70 G7 7i HO ' Tm Yb Lu “$93032 . 1689342! [73.04 174.967 S 15. Valu HmnlclI 70,2199 1995 iUl’M.‘ masses and Approved Names from httprfi'wwwxhem qmw.acukfiupnthWt.’ 'I'u: 307-11 I fmm CMZN, Mulch 13, 1995,1’35 I I2 l‘rum11leflwwwgsixiclzl |2u hlml I M from {WEN July 19, |099 H6 and ! LS Hum hilpflwww.ll:l,gov13cicnuc-i\xIiulcsIArchivcr‘elemunlsrl lfi-EJKhtml IllnSS ...
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This note was uploaded on 02/22/2012 for the course CHBE 2300 taught by Professor Kawajiri during the Spring '08 term at Georgia Institute of Technology.

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Exam1+key - Chemistry 23 11 Spring, 2009 Exam 1- Chapters 1...

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