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Unformatted text preview: Chem 309a Quiz 2: Complete the Quiz. Pet your answers on the scantron sheets. Be Sure
your perm numbers is on the scantron sheet. 5. Which of the following is a propagation step in the l‘reearattt'cel bromination ofmetltane?
!. 1112 tone-pair of electrons on nitrogen in the foltowing moieeuie reside in what type of A) CHJ- + Brv mm»- CH ,Br
8} Br; -—~—-‘-’-—-I— 2 Br » C) C“;- + Br; WCHIBr + 8r- CHy + CH,» ”—‘m-"I-‘CchHJ A} 5;? 7- 0)
Er- + Br- my» Br 2
B) spa .
g; :P 6. The following represéms what functional group?
) - R’o‘n
2. What is the name given to the Newman projection ofthe butane confonnation shown
here? A) ester
E) ketotte 7. What wouid be the correct name oftlte foliowing’.’ . CH3~CM2-CH2-CH—CH3
A) anti I
B) gauche CHQHCHg-‘Ci‘l-CHQE—GHQ
C) staggered -
D) eclipseti A) 3-(sec-pentyltpentane
E) skewed I) Semylwd-melhylheptane
. C) Msee-butyllitexane
3. The correct name oftlte following moiecule would be 1)) SuelhyH-methylheptane E) J—ethyM-pmpyipentanc 8. What statement is true oftite foliowiug energy diagram? A) 2ethyl~3.3-dirnethyiheptane
C) 3,4.4-trimethyloclane D) Zwbutyl-S-methylpentane
E) Lace-bitty!-2-metliyllaexane SM
4. Consider the potential energy diagram for rotation about the C2—C3 banal in pentane. prod l
The position marked "A" mostiikeiy corresponds to which of the l‘oliuwmg Newman
projections? A) For irreversible reactions, product I wit] dominate. B) For reversible reactions, product 2 will dominate at equiiibrium.
C) For reversible reactions, equal mounts of l and. 2 will be formed. D} For irreversible reactions, equal amounts of i and 2 wiil be formed.
E) None of the above are true. 9. How many diﬁ‘erent resonance structures can be drawn for the benzyl cation (shown
below) which place the plus charge on a carbon atom in the ring? 1'
m3 59953: i
6 Angle of Rotation l0. Which ct‘tlte Eotlom‘ng is considered to be a nucteepiiiie‘?
H3 A) CH3Ct H
u Ciigci'igcﬂj CH3
H H H H 1” 3 - CH} E) H C) =NH5
their; 6*) it
C if; / H; H T6
H E} C“!
t H l
C) CH3CH3 t
H CH; D} R A)
B) I I. Which ofthe following is not considered a Lewis acid? ill. The most stable conformation of Cl; I,3—din1ethylcyclohexauc has how many hydrogen
H8 atoms in axial positions?
A) A) 4
B} CHJOH B} 5
C) MCI; C) 6
EH3 0) 3
H30— E) none chime
D) CH; 20. “the following Newman projection represents which molecute?
[2. Which cftltc following contains the isohtnyl group? Ham-120326 crust-t; A) (CH3)2CHCH2CI
B) (CHﬂiCCI 5 H CHchch3
c; cmcnzcmcnncn ‘Cﬁe D) CH3CH2CH2CH2C1 :- JEL None oftltese A%/
[3. Calculate AG" for the following reaction at 25 ”C and A530
CH.1 t Br; W'- errata: "i 53‘ Bond Aim 3mm CH3 (3-0 33 that. mt c-l-t '39 that mail C-Br I53 tlcai'mnlt H -Br 37 “(61 until 3 33.13
Br- Br 46 (on mull ’ A) —la kcah'mol B) to itcah‘rnol . C)
C) 34 Real/moi D) .34 kcalftnol E) None ofthese iii E) E4. Which of the following has the highest pKa? )
A) Iii ' B} NH: C) HNO; E)
D) CH3COOli E) "2304 2L Which would be the most stable conformation nitrous-lmethyl—3-isopropylcyclohcxane?
' . . Citron )
l5. Which one oftite reactions below will not proceed and accounts for why lthlnB added to a H 3 2
lice-radical chlorination or hromination will grcatly slow or even slap the reaction? H
A) (333' + I‘ --—i-— CH 3| A)
hv CH; 533353): B) I; -—-—-+- 2 IV M H C) CH,- + 12 -———--u CH3! + 1. a) H
DCH¢+lcmm->~CH3-+Hl H H , Mama»
E) t- + hwy—l; C) ”33
H 16. Which of the following reaction types are typical ofalkanes? CHICHalz A) addition I l B) elimination CH C) radical substitution 0) 3 D) reduction ' CH, 9 El more than one at" these is correct. MCHICHQ; H I7. Which of the following is not true ofﬁce-radical halogenaticn reactions? 5’ A) Fluorine is more reactive titan chlorine in these reactions. _ _
B) Brontirtc is more selective than chlorine. 22. What would be the proper name ofthe Follow-trig, C) The reactions require either light or high temperatures to proceed
D) Bromicatioos are faster than chlorinations.
ii) 'l‘hcsc reactions an: irreversible‘ 18, The following molecule belongs to a class ofcontpoumis known as allcrtes. Based on Eirfnowlcdgc of bonding, prerlict the hybridization critic carbon atom indicated by the A) c: s-l-tctt-h utyi «turncthyl 0y cl on c N one B) traus- t -icrt-butyl-t~methylcycioitcxane C) axiatxqualorialul~tertobutyl—4vmclhylcyciohexane
D) 05- l —isopmpylv-d'melhylcyclohcxane I!) trans-t-isupropyI»4~methylcyciohcxanc 23‘ Hypcrconjugation is MOST useful for stabilizing Which of the following:
A) neopentyl radical A B) Ian-hutyl radical
B, SP2 C) isopmpyi radical
C) 5'”! D) cthyl radical D: in pf 12) methyl radical E) a itypcrvalcnt carbon 24 Which 0mm follows'ng disubstinned cyciohexancs could exist £21 a conformation which has 30. Which oflhe Following could have both methyl groups in an equatorial orientation? both groups equatorial? CH3
A) cIs—lj—dt'methylcyclohexane CH3
C) Irarts—lJ-dimemyicyclohexane A)
D) cis-l,2-dime:hylcyclohexano . CH,
E) all or none can have both groups equatona].
25, in a carbon radical, the carbon possesses how many valence electrons? ‘
A) 4 CH,
B) 5 B)
C) 6 cu,
26. Give the relative sanctivlly in decreasing order for free radical halogenatiou of(CH3)3CH. CH3
A) F >‘ Ct >Br C, :
a} CI>Br>F cu,
C) Br > F > Cl
D) Br 3' CI > F .
E) I > F > C!
27. Which ofthe following slnxctures represent sis-I .4-dimclhyicyclohexane? CH,
5) 3 I. What-is the correct name for the following molecule? A) mu 8) ESL!” C) ll & III B) Aliol'lhese
E) Noneo'fthese A) l-cMoro-2—memyI-d-propylcyclopenlane
C) I~chloro-5-methyl-3-propylcyclopemanu ‘ , D) S-methyi-luchloro—Ll—pmpylcylopunlanc
284 Rank Ihc FOIIDWI'IIS radicals in decreasing “‘5‘” "filabm'y- E) l-chlow-3-propyi-S-melhyicyclopenkane - CH; (Cﬂslac ' Oval; CHJClF—éﬂz 32. Which. if either. ofthe two isomers ofthe cornpound shown below would be the more
I 2 ' 4 stable?
A) 3 > 4 > 2 > E
B) 3 > 2 > :3 > t
C} 2 > 3 > 4 > i
D) 2 > 4 > 3 > I
E) l > 2 > 3 > 4
_ . . l - . I la! d 'vat‘ve A) Ci: is more stable.
29. Which oflhc followmg hydrocarbons would yteld on Y a SIRS P- ENN“: 0“) e" l B) Trans is more 5.35";
under free radical chlotinalion comiitions? (Clthv) C) Both are mm“), slable.
D) Neither is slablc.
E) There is no way to predict this.
B 33. What is the most stable conformation oftrans»l-ﬁuoro—4~methylcyclohexane?
B) A, PM
“J B) F
D) . F
DA [3) m0“:
El E, two“ 34. Although ﬁve— and six-membered rings are generally the most stable, why is cyclopcnlane
less stable Ihan cyclohexane? A) The angles in cyclopentane deviate signiﬁcantly tiom the tetrahedral angle. B] Five—manhunt] tings have trans annular Enteractions. C) Five-mumbercd rings have cclipsing hydrogcns. D) Piano: cyclotzexane has bond angles closer to 309“. E) Largo: tings are always more stable than smollet rings. 35. Which of the following comedy shows the Newman projection along a C—C bond in 441 Predict the M AJOR Fretted oftlt e following reaction:
cyclottcttatte? (the squigglmi indicate where Ihe rest ofthe ring is attached) Bf; I Jig!“ m—w
A) A 5 c)
B) B .
C) C .
1:3; E D) Br
36. Whichol‘ the following is NOT in its most stable confonrtatiun? E) m Cl A) CH1
1 CH3CH; B M , ) A) pentane
H t: a tan C) Hjcmoc 3 ) It 6 C) 3—ethylbutarte H00 D) hexane
D) I Br 5) All of these are in their most stable conﬁrm-ration 42. What is the eerreet Nem‘ttttn projection for the foEiowittg molecute‘! 31. Which ofthe foltowing statements about eonfortrtatiorts Ofmelhylcyclohettarte is true? WC": m ‘ cuJ r K
. Cl CH3
A) The energy barrier to intereottvert these is too high to be echteved at room temperature.
B) The two forms are in equilibrium and are present in equal amounts at room temperature. BrQCmCI-t,
C} The two forms are not in equilibrium but are present in equal amounts at room temperature. A) CH3
D) The two forms are in equitihrtum but are not present in equal amounts at room temperature. t H926”;
E.) The two forms are not in equilibrium and are not present in equal mounts at room Ct @533
38. Which of the following is TRUE for an early transition elate: 3) CH3
A) The starting materials resemble the products. H23”,
B) ’t‘he reaction proceeds very slowly. Ctécm
C} The transition state resembles the reactants.
D) The transition state resembles the products. ”SCHEC 3’
E) Both it and c. (3) CH3
39, Which oftlte carbon-carbon bonds indicated would be the weakest? Ct Cit,
E) Norse ofthcse
43. Which ot‘the following compounds has the highest heat of combustion per Cl}; group?
A) A D) eyetohexene
(RI; 3 E) “H have equal AHeartelrttrttietn
[a E 44. in a free radical termination step: A) an initiator starts a chain reaction. 3) free radicals recombine with one another.
C} a radical reacts to form another radical.
D) the activation energy is high. E) a reactive intonat‘ediate is formed. ...
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- Fall '09
- Organic chemistry