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PracticeFinal1 - li/mC‘f/CC flnq/ Organic Chemistry...

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Unformatted text preview: li/mC‘f/CC flnq/ Organic Chemistry Oil-Line: The Workbook ‘187 Practice Examinations The following pages contain six 25-question practice examinations covering sections in the first twent:"- four chapters in John McMurry’s Organic Chemistry, and two fifty-question examinations covering all twenty—four chapters. These examinations are multiple—choice and are written in the style that is often encountered on pre-professional entrance examinations (ie, the MCAT or graduate school placement examinations). Because organic chemistry is a structural science, many classroom examinations feature questions in which students must draw structures and mechanisms, such as those seen in the bulk of this workbook. While this approach is very effective at teaching the fundamentals of organic chemistry, students often receive little practice with the multiple—choice format, and sometimes feel poorly prepared for this type of standardized testing. In most of the examinations in this section, references are provided referring the student back to McMurry’s fifth edition. These examinations also appear on the accompanying CD, and the answers to the questions, together with a short explanation are also presented. As always, it is recommended that you complete these exercises in your workbook prior to interactively checking your answers on the CD-tutorial. Practice Exam #1 — NIcMurry, Chapters 1 — 6 (Use the following information for questions 1-2.) Consider the molecule NHZCl, chloroamine. [see MCMurry, Section 1.6] ,..i The shape of the molecule is a. tetrahedral b. trigonal planar c. pyramidal d. flat e. octahedral 2. The arrangement of electron pairs about the central N atom is [see McMurry, Section 1.6] a. tetrahedral ' b. trigonal planar c. pyramidal d. flat e. octahedral 3. Chloroamine (NI-{2CD [see McMurry, Section 2.2] a. has a strong bond dipoles and a net dipole moment. b. has no bond dipoles and a net overall dipole moment. c. has a strong bond dipoles and NO net overall dipole moment. d. has no bond dipoles bond dipoles and NO net dipole moment. 4. Which of the following substances is the worst Bronsted—Lowry acid? [see McMurry, Section 2.7] CH4 d. H2504 b. HCl 6. H3 P04 c. HClO3 5. Which element in CHEOCHZLi is the most electronegative? {see McMurry, Section 2.1] a. C d. Li b. H e. H3 c. O 6. Which of the following substances is the best Lewis acid? [see McMurry, Section 2.11] a. CHKCHZOH d. H28 b. NH (CHE).2 e. BF3 c. H 2 I Choose the structure that contains the listec :‘ainchoncil group: {see -"-.-’lc}viurry, Section 3.1] CH1 coon ...J \, i. among—fl I _ \\m/r fiCN @010 a I) C d c 7. Alcohol Q, rboxy‘lic acid 00 Ethyl group if). Aldehyde h.) p_\ Amide M iv How many of the constih tional ? VI somcrs of Chi—t], can be correctly named as “butane” using the lUPAC naming system? {see MCM‘ r-a Jrry, Section 312:3] [X [M m I.— "T D h) ~— L- (D Q- 4: VJ (Use the foliovi’ing information for questions lf—‘---l4) Consider the following molecule: HA. ,rCHZCHK g lil’v‘m A Form B all - l a. A is more stable than due to reduced 7,3—diaxiat istabilization. D. B is more stable than A to reduced 1,3—diaxial gestabilization —. 73. \Nhich of the following is we: {set “Mitt-flurry, Se“ -. c. A is more stable than 3 due to enhanced l,3—cliaxial stabilization d. B is more stable than A clue to enhanced 1,3—cliaxial stabilization e. A and B are exactly the SAME i"v’iOl.7:iC'ULE. 34. Which of the followrng statements is(are) correct? [see i'vicMLlrry. Section 4.11] a. A can be converted into 3 by ring flip. b. A can be converted into by single rotation about a single bond. c. A and B are exactly the SAME MOLECULE. c. Both a and i7 are correct. (1. None of these is correct. 15. Consider the conformers of pentane defined. by rotation about the C2-C3 bond axis. Which of the folloWing Newman progections represents the. Loggth energy minima? isee McMurry, Section 4.3] CH} CH1 ‘5 CH3 _ ' CIZHZCHf) CtlgCHq ‘ H H ' (‘}J"C‘l{§ 1’-\ . , xh 17L ' H . _ .. . 7 : , . ,"IY 1/L\\.L, 7;}< LI />L H H H ii h ~/ A ; CH1 , i [ ' e. both a and b H i; <‘¥"';:(‘U~ H a E; c d Organic Chemistry On-Line: The Workbook 1 89 16. Ring strain is very high for cyclopropane. The best explanation for this is [see McMurry, Section 4.3,7] a. Smaller bond angles produce increased eclipsing interactions. b. The molecules are deficient in H compared to non—cyclic alkanes. c. Orbital overlap is reduced by the strained geometry. d. The molecules are flat. e. More than one of the above. 17. Which of the following statements is(are) correct? [see McMurry, Section 5.2] a. Heterolytic cleavage leads to radical (unpaired—electron) reactions. b. Homolytic cleavage leads to polar (charged—species) reactions. -c. Both a and b are correct. d. Neither :1 nor b are correct. (Use the following information for questions 18~19.) Consider the polar reaction shown below. H H H H._ G >_—_-< + HCI ~——z, H H H H 18. The first step involves [see McMurry, Section 5.5] a. attack of the Cl on the double bond . loss of a proton (H+ )from the alkene b c. attack on the proton of HCl by the sigma~bond electrons between the CS Cl attack on the proton of HCl by the pi-bond electrons between the CS e . formation ofa negatively charged carbon species, a carbanion 19. In the second step of this reaction a Cl is a nucleophile and the carbocation is an electrophile b. the HCl proton is a nucleophile c. the sigma—bond electrons act as a electrophile d. the pi—bond electrons act as an electrophile e. homolytic cleavage occurs Use the following reaction for Questions 20 ~ 23. H H. "'-H A Cl H CH3 HCl // Cl H H: “th H CH. 20. Which of the products above is preferred? [see McMurry, Section 6.9] a. A b. B c. Neither is preferred. There is a 50:50 mix of the two. cl. The reaction does not occur under these conditions. .190 21. Which of the following intermediates would lead to product A if the reaction leading to that prod- uctdid occur? [see McMurry, Section 69,10] <3—'CH3 r—CH3 C b' <9 51- H3 HZC C. Neither intermediate is possible. 22. Which of the following statements is TRUE? [see McMurry, Section 6.9,10] a. A is the preferred product because the reaction leading to A is slower than that leading to B. b. B is the preferred product because the reaction leading to B is slower than that leading to A. c. A is the preferred product because the intermediate leading to A is lower in energy. d. B is the preferred product because the intermediate leading to B is lower in energy. e. The reaction does not occur. 23. The rule governing the product distribution is [see McMurry, Section 6.9] a. Zaitsev’s Rule Markovnikov’s Rule Carbocation rearrangement The “nonspecific rule” The Rule of Thumb one? 24. Which of the following is the correct designation for the molecule shown? [see McMurry, Section MEL-mm 6.6] HOH3C CH3 /: \ H3C H a. 0'5 ' d Z b. trans e. None of these. c E 25. Compared to single bonds, double bonds are: a. longer and weaker d. shorter and stronger b. shorter and weaker e. orthogonal r c. longer and stronger Organic: Chemistry On-Line: The Workbook 191 Practice Exam #2 — McMurry, Chapters 7 — 12 1. What is the major product ( X ) when styrene (shown below) is reacted with H2 over a Ni catalytic surface? [see [VIC/Murry, Section 7.7] \ +Hg——~>x .\ 1' I r 7? LII; Ch 0 Q“ o e. No reaction occurs under these conditions. 2. Which product(s) would be produced by acid catalyzed dehydration of the following alcohol? [see McMurry, Section 7.1] 0H H3C\‘/\/CH3 CH3 a 2-methylpentene b 2—methyl—2—pentene c. Z—niethylpentene mi 2-methyl-2-pentene d 4—methyl—l-pentene e all of these 3. What product would result from the reaction of ’l,Z—dimethylcyclohexene with hydrogen gas in the presence of a Pt catalyst? [see McMurry, Section 7.7] CH3 (1. 1 9 2 VA 7 7 _ 4. The role of peroxides in the polymerization of ethylene is [see McMurry, Section 7.11] a. radical producing chain initiator b. Lewis Acid producing chain initiator c. polar reaction catalyst d. radical producing chain propagator e. radical producing chain terminator l f a 5. A triple bond is composed of: [see Man/furry, Section 8.1] 'a. three sigma bonds b. two sigma bonds and one pi bond I c. one sigma bond and two pi bonds I (1. sp3 bonds I e. sp bonds 6. Which of the following is required to form an acetylide anion? [see MCA/Iurry, Section 8.8] a. a VERY powerful base. . a terminal alkyne c. peroxides I d. a aid b e. b m c 7. Which of the following is a good operational way to identify a chiral center? [see Mo’vlz/zrry, Section 9.1,2] a. Determine if a plane of symmetr 7 exists. Determine if there are four different attachments at a carbon center. b. c. Check for the existence of mirror images. (:1. See if the molecule is optically active (Le. does it have color). 8. The reaction shown below can be said to be: a. stereoselective. b. regioselective. c. both a and b d. neither a mi; b The answer choices make no sense in this context {D 9. Molecules that rotate plane polarized light to the left are: [see AMA/furry, Section 9.3,4] a. levorotary b. dextrorotary c. R d. S (The following information and answer choiCes will be used for Questions 10 ~11.) Llassify the following pair of streoisomers as: [see Wham/w, Section 9.1] enantiomers b. diasteroemers c. identical d. identical and meso compounds different chemical compounds and not isomeric 12. 13. 14. Organic Chemistry Ora-Line: The l-i’brfcbook 1 93 Why is preparing a rnonohaloalkane by radical reaction with X a poor reaction synthetically? [see NRA/[wry Section 10.4] k a. b. c. d. The reaction is slow, The reaction is not regioselective. The reaction requires enormous light flux to begin. The reaction is massively exothermic and produces a huge amount of heat. Which of the following is the most stable radical? [see McMurry, Section 10.6] a. b. H Hun" . J/L\CH2 R I 1 n cnz R Rn R '.ul"' \ \CH2 R / $6112 Why is SOC!2 used instead of HCl to replace —OH groups on secondary alcohols? [see Merl/Tum], Section 10.7] SOCl2 is resonance stabilized, leader to faster reaction. a b. c. d. There are no radical byproducts with SOCIZ. SOClZ has a steric advantage over the chloride anion. Reactions are run under mild conditions, leading to fewer rearrangements. Which of the following reagents are used to produce a Grignard Reagent? [see McA/lurry, Section law a. EDD—00‘ Ce ,/ H30* X / Mg RH / NBS SOCl2 / Mg THF / M g 194 (Use the following for questions 16 — 17.) The monosubstitution reaction of methane with Cl2 proceeds by a stepwise radical mechanism in the presence of UV light. Classify each of the following reactions as: [see Mcery, Section 10.4] a chain doubling b. chain initiating c. chain propagating d chain terminating e none of these 15 CH4 + c] ———> 'cH3 + HCl 17, 2C1 ———> c12 18. Consider nucleophilic substitution reactions of alkylhalides, where a moderately reactive nucleophile is used. Under which of the followin sets of conditions is the 5N2 mechanism most likely predominant? [see McMm‘ry, Section 11.4,5 a. primary substrate, acidic conditions b. secondary substrate, acidic conditions c. tertiary substrate, acidic conditions d. secondary substrate, basic conditions e. cannot differentiate Use the following reaction for Questions 19 and 20. [see McMurry, Section 11.5] HO . A. H—O_> + F 2 110' A _V _ B. CH3CH2CH2I W CH3LI~IQLH20H + I 2 19. What is the predominant mechanism type for both reactions? a. 5N1 b. 5N2 _c. E1 d. E2 e. radical 20. Which reaction is faster and why? a. A, because F‘ is a better leaving group that l’ b. B, because I‘ is a better leaving group that F‘ e c. A, because F stabilizes the reactant better than I d B, because I stabilizes the reactant better than F . The reaction rates are equivalent. Use the following answer choices for questions 21 — 24. I. substitution VI. unimolecular L- . lI. elimination VII. nucleophilic llI. addition VIII. electrophilic .. L W. rearrangement IX. single step V bimolecular X. multiple step 21. An E1 reaction is: [see McMurry, Section 11.14] a. VIII, IX b, VIII, IV, IIX c. VIII, VI d. II, IX e. II, VI 22. 23. 24. 25. Organic Chemistry Un-Iine: The Whrkboak 1 ‘36 An SNI reaction is: [see McMurry, Section 11.6] a. I, VIII b. I, VI, IX c. I, X d. III, VI e. III, VII, X An E2 reaction is: [see MCMm‘ry, Section 11.11] a. II, IX, b, II, X, VI C. II, IX, VI d. IV, VIII, VI e. IV, VIII, IX An 8N2 reaction is: [see McMurry, Section 11.4,5] a. I, X b. I, IX, VII c. I, V, X d. III, V e. III, X A synthetic chemist ertormed a series of reactions designed to produce bonds between C and N. On analysis of the Hgspectra of the resultin compounds, there were characteristic bands resulting from various types of C-——N connections. T e observed bands fell into three ranges: [see McMurry, Section 12.9] I. 1020—1250 cm“ 2. 1471—1689 cm'I 3. 2000—2273 cm" The bands were assigned (in order 1,2, 3) to functional groups as: nitrile, imine, amine imine, nitrile, amine a. amine, nitrile, imine d b. amine, imine, nitrile e. c. nitrile, amine, imine 196 Practice Exam #3 — McMurry, Chapters 13 - 16 (Use the following five answer choices and the molecule shown below for questions 1 — 5 relating to NMR spectroscopy. Answers may be used more than once.) 5 cu. O—CH 4 _ / \ HgC—CH2 CHg . .5 V l 2 3 0 ' A. downfield q B. upfield C. quartet I D. triplet l E. equivalent 1. The protons labeled 2 are relative to protons 1. [see McMurry, Section 13.3] 2. The protons labeled 3 are relative to protons 5. [see McMurry, Section 13.3, 8] l 3. The NMR signal from protons labeled 2 are split into a V . [see McMurry, Section 13.11] 4 The NMR signal from protons labeled 1 are split into a . [see McMurry, Section 13.11] 5. A lei shielded proton falls on an NMR spectrum in relation to a more shielded proton. [see McMurr-y, Table 13.3] 6. A compound of the formula CSHIOO gave the following spectral information: 1H Spectrum: lR Spectrum: 6 H doublet @ 5 1.10 strong peak at 1720 cm’1 3 H singlet @ 5 2.10 1 H septet @ 8 2.50 Which of the following is a reasonable structure for the compound? [see McMurry, Section 13.3 & Chapter 12] Organic Chemistry Un-me; 1 Inc "WWW" ‘7. The 1,2 monoaddition product(s) for HCl reacting with 2,4—hexadiene is(are) [see MCMurry, Section 14.5] a. No reaction. b. 5—chloro-2-hexene c. 4—chloro—2~hexene d. 2-chloro—3-hexene e. more than one of the above (Use the following information for questions 8 ~ 11.) [see MCMurry, Section 14.12 fit Chapters 12 and 13] ’H NMR: 3 H s @ 1.96 5 Molecular Formula: CgHmO2 2 H S @ 5.00 5 5 H s @ 7.22 5 UV—Visible: Intense peak at 255 nm Major IR peaks: 1610, 1495,1735 cm" 8. Which of the following is ruled out by the IR information? a. carboxylic acid b. extended conjugated system. c. ester d. acid anhydride e. aromatic systems The NMR peak at 7.225 is indicative of the presence of a(n) [see McMurry, Section 13.9] \D a. carboxylic acid. b. extended conjugated system. c. ester. d. acid anhyd ride. e. aromatic system. 1.0. The fact that all of the peaks in the NMR are singlets means that [see McMm‘ry, Section 13.9] a. a decoupling signal has been added to the spectrum to reduce clutter. b. the three sets of hydrogens are interchangeable with one another on the NMR timescale. c. equivalent protons on adjacent carbons do not spilt one another. d. the three sets of hydrogens are isolated from one another. e. no information can be gained. '11. Which of the following is the best structure given the information above? [see McMurz/y, Section 13.9, 14.12] a. no WOH d. Drganic Chemistry On—Line: The Workbook ;. II Practice Exam #5 -— “Alkanes and Cycloalkanes 1. The most correct IUPAC name for the molecule shown on the right is. a. l-aminodi0xy—3,4-dimethylcyclopentane b. l,2~dimethyl—4-nitrocyclopentane c. l,2—dimethylcyclopemyl—Al—nitrate d. 3,4—dimethyl—l—nitrocyclopentane e. l~aminO—2,3—dimethylcyclopentane (JEN 2. The most correct IUPAC name for the molecule shown on the right is: a. l—Chloromethyl—1,4—dichlorohexanc b. l~chloroethyl—l—(l,4—dichloro)hexane c. l.2~dichloroethyl—3—chloropcntane d. 1,2,5-trichloroheptane e. 3,6—dichlorohexyl—6—(l—chlorOJmethane c; 3. The most correct IUPAC name for" the molecule shown on the right is: a. 5—ethyl-3—methyl-1-bromocyclohexane b. l—br0mo—(3—methyl—5-ethyl)cyclohexane c. l~bromo-3—ethyl—S—methylcyclohexane d. 2-(3—bromo—5—methylcyclohexyl)ethane e. 3vethyl—S—methyl—bromocyclohexane 4. The most correct IUPAC name for the molecule il’lOWfl on the right is: a. l—(3—brom0—2-methylbutyl)cyclopropane b. l—bromo—(3—methyl—5—ethyI)cyclohexane c. 3—brom0—1—cyclopropyl»2—methylbutane d. 2—(3—br0mo~5—methylcyclohexyl)ethane e. 3-bromo—l—cycl0propyl—2‘methylbutane 3. The most con'e’ct [UPAC name for the molecule shown on the right is: l~chl0r0—27methyl74,4—dibromocyclohexane 1,l—dibr0mo~4-chloro—3—methylcyclohexane transvl . l —dibromo—4—chloro—3—methylcyclohexone 1. l —dibromo-4—chloromethylcyclohexane 051.06.” 6. The most correct IUPAC name for the molecule shown on the right is: . 3—(2—bromoethyl)—3—methylhexane l—br0n10—3—e(hyl—3—methylhexane l—bromo—3~propyl—3—methylpentane . 3—(2—bromoethyl)—3»ethylpentane . 2—(2»bromoethyl)—2»ethylpentane one?” 7. The most correct IUPAC name. for the molecule shown on the right is: a. cis—1—chloro—3—methylcyclohexane b. cis—1—chloromethylcyclohexane c. 1,3—diaxial»chloromethylcyclohexane d. trans—l~chloro~3»methylcyclohexane e. Cis—lrchloroetranS—3~melhylcyclohexane 8. The most correct lUPAC name for the molecule showr on the right is: Ira/15> l—chloro—3»( l —methylpropyl)cyclobutane cis— l-(3—chlorocyclobutyl)— l—methylpropane l—(ci5—3—chIorocyclobuty l)— l-methylpmpane trans~ l —(3—chlorocyclobutyl)~ l~methylpr0pane cis— l-chloro—3—( l —methylpropyl)cyclobutene runes? CH] CHgCl-{g Br CH3 Br Br I Br . 4—chloro—l,I—dibr0mo—3—methylcyclohexane C)‘ \\/___ Cl H /\ \%\cn3 ‘\J H Cl / r H ) Hui $9.6 9. The two molecules shown on the. right are: (EH3 Ell t i _ _ i l # __n a . identical H CN l\C VH3 19 . constitutional isomers H_C_CHI H3C _C_CHZCH1 c . conformational isomers l ’ _| ' d . different Compounds CHZCH} H e . isomeric. but not constitutional isomers (2) 10. Which statement is no; .rw regarding the molecule on the right? I]. 14. a ., methyl groups (l) (2) are trans to each other in. methyl Uroups (2) 8: (3) are mum to each other c . metla,‘ Lsmups (l) & (3)21re Clj to each other . in 1h: most stable eoni'ormation‘ methyl (3) is equatorial e . it :imhyl group (3) is equatorial. methyl (2) will be axial The two irioletrnlsr: shown on the right are: 2;. identical ()H OH E . constitutional isomers -'....COOH and C. conformational isomers CHsCH2 CH CF (1. rotzimers, but not cortformutional isomers l ‘3 COOH 9. different chemical compounds ‘Jilliiel'i is not (we regarding the molecule shown on the right? C(CH3)3 a. the ring junction is Cir H b. the icrt»btityl group is in an equatodal (stable) position 6. the methyl group is (is to the carbons in the ringjunction d. the compound Cilrli’iol undergo ring inversion I'D . the [C't't»l‘i‘.tiyl group is Cir, to the carbons in the ringjunction H 9 H CH} ii The two compounds shown below are: 2. identical E). constitutional isomers 2. different, and not isomers d. cis—tmns isomers \/H N and ii / l €th Cl ' The two compounds shown below are: ti. identiczii l3. constitutional isomers d. (is—trans isomers tgnzem l [C gum and H it: ’sa Cl ‘ CHZCH3 The two compounds shown below are: 21. identical h. constitutional isomers c. different, and not isomers d. cis-irans isomers (1.”? P H CH3 i I ,41..;5{l\14;/7l\ C H“ and ’R H / ' 3 ll 3'1 ~.\./,/7*~~\\.,L.~'i V - l at l" l ‘ H3L Organic Chemistry (ht—Line: The Workbook 207 16. The two compounds shown below are: a. identical 1). constitutional isomers c. different. and not isomers ti. (:i'iuirztiii' isomers H l l11('\C//C\Cy , 11 1 ‘ I l ‘ dnd W\\ H C\ H/ Nu, 17‘ The two compounds shown below are: 2. identical 1). constitutional isomers c. different. and not isomers ‘1; Liz's—Mans isomers l and ,L 13. The two compounds shown below are: a. identical b. constitutional isomers c. differenL and not isomers d. (‘i.r~rr‘ali5 isomers l CH3CH2(CHCH3)CHZCH2Cl and \/\/\Cl 19. The two compounds shown below are: 3. identical b. constitutional isomers c. different. and not isomers d. CiS-U‘mls isomers ._ TZT‘i\ \ / CH3 and up —-(\\\——//~—-CI~L H3C 20. Which of the molecules shown below is Z— l ,Z—dichlorO» l—ethylcyclopentnne? a .Cl ,C1 b. k C . ,CHQCHj, (:1. /Cl H _ / 1H /\ ll Ci ‘L‘flr‘l 23. Which of the molecules shown below is E-l,3—dimethylcyclohexane‘? 3 Cl CH 2Ctr, H . H h . CH H c . H d . H Hf , . Y ' I 3 H \ CHI /\ \4‘\CH2 H H CH} , ch ‘ Hg" CHI - a 22. Which of the molecules shown below is 2‘2vdimethylbutnne'? a. b . c. d, a H LH; CH3 CH3CH2 H Vk/ Cl . {(7 , r‘w K. H CH3 H I 3" \(‘H \CH} , ‘ CHa / 2 CH2 CrIZCH3 H CH3 . ...
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PracticeFinal1 - li/mC‘f/CC flnq/ Organic Chemistry...

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