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322af06_e1_key - “wwwww CHEMISTRY 322aL/325aL Please:9...

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Unformatted text preview: “wwwww CHEMISTRY 322aL/325aL Please :9 \! EXAM NO. 1 Print Last Name SEPTEMBER 13, 2006 First Name First 4 digits of USC ID _ _ _ _ --XXXX-XX name of TA Grader (1) (20) __ (2) (10) _ (3) (15) __ (4) (20) _ (5) (15) __ (6) (10) _ (7) (10) _ (100) first letter of last name I will observe all the rules of Academic Integrity while taking this exam. Signature Chemistry 322a/ 325a -2- Name Exam No. 1 (1) (20)) Answer the following questions. (A) (4) Provide detailed dash-line structural formulas for the two organic molecules written below as condensed formulas. Your detailed structures must ShOW all the atoms; and all the bonding and nonbonding electron pairs. Show each pair of bonding electrons as a dash or line and show each nonbonding electron pair as dots. Draw the structures inside the boxes. (CH3)2C=CHCH2NH2 CH3CH(OH)CH20CH3 (B) (2) Draw inside the box to the right, a bond-line (abbreviated) structure of the condensed formula written below the box. Cl CH3CH2CHC1CH2CH(Cl—I3)2 (C) (6) Provide the missing formal charges in the structures below where all valence level electrons are shown. Place the charges immediatel next to the atoms on which they reside. (D) (8) In the organic compounds below, identify each functional group by selecting the proper name from the list of choices and writing it on the line next to the arrow.. H2COCH3 9 U Q3 55‘ z : CHBCHzCCHZCI—ICE CCH3 (T Hm” ::> OCHZCH3 _ g 2 +03 g CHZCHfi)H m\¢o\\ o \ Choices: alkene, alkyne, alcohol, aldehyde, amide, amine, aromatic, carboxylic acid, ester, ether, ketone. Chemistry 322a/325a -3— Name Exam No. 1 (2) (10) Answer the following questions about the hydrogen phosphate dianion, HPO42_. (i) (2) The number of valence electrons in this ion is H g + 23 4:2, I. 32 | (ii) (3) Draw a Lewis structure of this ion by adding the missing valence-level electrons to the structure below. Use lines for all bonding electron pairs and dots for nonbonding electron pairs. Your structure must show formal charges and have the maximum number of bonds. or emu; \mX em‘t —‘ (iii) (3) Draw in the box below three resonance structures of th' ion that are the major contributors to the hybrid. 1- i w 6 (iv) (2) Draw the hybrid of this ion in the box below. Indicate the bond order (number of two- electron bonds) for the P-O bonds and the amount of charge on each oxyg'én atom. @ Chemistry 322a / 325a -4- Name Exam No. 1 (3) (15) There are three constitutional isomers of C3H4, two are linear structures and one is a ring structure. Answer the questions below about these simple organic structures. (A) (6) Draw dash-line structural formulas of the three isomers inside the following boxes according to the descriptions below the boxes. Show all atoms and bonds in your structures and follow the octet rule for carbon. Constitutional Isomers of QR; a linear structure where a linear Structure Where 3 a ring structure with 2 OH all 4 C-H bonds are the OH bonds are the same bonds of one length and two same length and the Carbon length and one is a different C-H bonds of a different -Carbon bonds are the same length and the carbon-carbon length and two caern—carbon length bonds are different lengths bonds of the same length and one of a different length (B)(6) Explain the linear structure of isomer A using hybrid orbital theory by identifying the hybridization states of the three carbons on the lines in the box below. Draw a picture that shows the orbitals used in bonding by C2, properly projected from C2 and labeled as 5, sp, sp2 or sp3. Do not draw orbitals used by the other atoms. isomer A 1 L fli hybridization states: C1 SP C2 ‘39 C3 g P S 9 C I 3 (C) (3) Identify the hybridization state of each carbon in isomer B by re . wing the dash-line structure in the box below (an orbital picture is not required) and writing the hybridization state (sp, sp2 or sp3) immediately below each carbon atom. isomer B hybridization states of C Chemistry 322a / 325a radian—L M7 4mg (4) (20) Circle the correct answer for each. question or statement below. (A) The molecular formula of the structure below is 0 4f 7 L (circle anSWer below) M M DCHZOH C6H80 C6H120 C6H14O (J (B) In the hydrocarbon below, the C-H bond 51 1? H—C =C— --CEC—H t FEE—H t C H A -C is the shotest an t e strongest. -B is the longest and the strongest. (C) According to the VSEPR model, which of the following chemical species has or have a trigonal planar geometry around the central atom? (circe answer below) only 111 I, II and III III IV ( II and III 5 all of them (D) In the pairs below, the structures with the higher boiling points are pair A pair B (CH3)3N CH3CH2CH2NH2 CH3CHZOCH3 CH3CH2CHZOH I II I II (circle correct answer) A I, B I A I, B II A II, B I (E) In the structure below, the labeled carbons that are sp2 hybridized are I II B A (circle answer below) #1 H l l CH3- H_Czc_ _CHZOCH3 C and D B, C and D \ x C only D C,D and E D l Chemistry 322a/ 325a -6- Name Exam No. 1 / m (4) Contd. fl 4 Y ("l/é (F) Identify the primary amines among the structures below. (FHB (circle answer below) CH3q-NH2 only I I and II CH3 NH2 ( I, 111, IV) I, II, 111, IV IV I II III CH3CH2CH2NH2 CH3CH2NHCH2CH3 (G) Identify the relationship between the structures in each pair below as constitutional isomers (C1) or resonance structures (RS). ircle answer below) C _ + + .. H—CEN; :CEKJ—H H2C=I\II-H Hzc—Ig-H ICI, 11 c1 H \_fl_—J %__J IRS, 11 RS I RS, 11 c1 I 11 (H) Which of the following alkenes (C4H6C12) exist as as and trans isomers? (circle answer below) f\ I II III I and II I, II and III (I) The regular increase in boiling point of the alkanes with increasing size, as seen below, is due to CH4 CH3CH3 CH3CH2CH3 CH3CH2CH2CH3 BP(°C) -162 -88.5 -42 0 (circle correct statement below) -in reasin intermolecular h dro en bondi —increasing importance of van der Waals ( —1ncrea51ng permanen 1po e-permanen —the better packing of the increasing rod-like structures. PM . London) Interachons. \ (J) The melting points of the three salts below are in the order from highest to lowest: (circle answer below) NH4+ Cl— NH4+ AC- Na+ Cl- . , . II>I>III I>II>III ammonium ammonlum sodium Chloride acetate chloride C: ) I II III Chemistry 322a / 325a -7- Name Exam No. 1 (5) (15) Answer the questions below. (A) (6) Provide detailed dash-line structures in the boxes below for the following organic compounds. All valence-level electrons (bonding and non-bonding) must be slhown. Show all covalent bonds as dashes or lines. propyl bromide diethylamine isopropyl methyl ether (B) (4) Provide detailed structures in the boxes below of organic compounds consistent with the descriptions below the boxes. All valence-level electrons (bonding and non-bonding) must be shown. Show all covalent bonds as dashes or lines. a tertiary amine C4I-I11N a secondary alcohol C3l-180 (C) (5) Ethene (HzCzCHz) and formaldehyde (H2C=O) have structures of comparable size (MW 2 28 and 30, respectively). Yet, their physical and chemical properties are very different. Assign the properties below of A and B below to these two compounds. A: bP ‘210C/ mp 92°C, soluble in water. MM-Q B: -103'70CI mp '1690C, inSOluble water_ Briefly explain the different solubilities of A and B in water in terms of specific intermolecular interactions. fibrmoA Ac it Y3 Cc ?o\o~x~ mo\¢_c ka {+\'\LMJ\ \% mmPDLP. i—‘orma\c\¢\\lclt\ ovvv'L unite «We COMPcfi-KL lg 0“th S‘l‘mmj SO\u,J°L —5t>\\!¢-~C5\” Henna-.C'HO’KS" “103+ \mTor—brwj ‘5 fl Q’vx‘l‘ \m‘KVmQ‘HUMS L _' o A . $D\~\.\—So\\l W “ng‘fi: QKWWLQ‘K. but-to 0.1M Q *‘an‘4 0‘ '4‘ -- / \ \ __ 'r’H C—O, 6‘ H garlvl C5: + Chemistry 322a/ 325a -8— Name Exam No. 1 (6) (10) Answer the questions below. (A) (4) Among each set of three structures below, circle the two that are the same constitutional isomer. qH3 on. (i) CH3CI-ICH2CI-12CI-I2CI-I3 CH3CI-IZCHCH2CH2CH3 CH3CH2cHCH2CH28CH3 CH3cH2cHCH2CH3 CH3 1&4 (m [dd/{H (B) (6) Write a second reasonable resonance structure of each Lewis str ture below. a CH3-CH—CH=CH—CI-I3 CHS—CHT—Q H -CH ‘ (7) (10) Provide the structure of the compound that answers the questions below. ("5 (A) (3) Provide a structure of the isomer of dichloroethene (CZI-IzClz) that has a molecular dipole moment of zero. (B) (3) Provide the structure of the M dichlorobenzene (C6H4C12, a l f. M f benzene where two H are replaced 0 by Cl) that has a molecular dipole moment of zero. (C) (4) Provide the structure of the amide, C3H7NO, that is incapable of hydrogen bonding in its liquid and solid states. ...
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