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Chem+8A+Spring+09+final+key

Chem+8A+Spring+09+final+key - Name Last CHEMISTRY 8A Spring...

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Unformatted text preview: Name: Last, CHEMISTRY 8A Spring 2009 Final Exam June 8, 2009 S. S. David (12 points) - (24p01ntS) _ (141mm) _ (16 points) (20 points) (8 points) ( 8 points) (10 points) ( 6 points) (10flnts) (200 points) (10 points) i Extra Credit First (PLEASE PRINT) Name: Last, First (PLEASE PRINT) 1. Appetizers and Finger Food (2 pts each/8 total). Place answer in box. i. Which of the following molecules would NOT be described as a trans isomer? 0 F o 0 ”SR/MR” ”3‘3on NOH H3C\/\CH3 A F B Hac c D ii. Where is the lone pair of electrons of the nitrogen atom in an amine molecule located? A) in an s orbital r,‘ B) in a p orbital b C) 1n an sp2 orbital D) 1n an sp3 2orbital E) 1n an Sp 3orbital iii. The following mechanistic step in a reaction is referred to as what? ‘ [A I A) elimination CH CH B) deprotonation “ac/\r 3 ’———' ”ac/\r 3 + H G) C) protonation ,0 D) electronification H G) H H iv. Which of the following describes a carbon-carbon double bond? A, l A) one sigma bond and one pi bond B) two sigma bonds and one pi bond C) one sigma bond and two pi bonds D) two sigma bonds and two pi bonds Vi. Which of the following is the correct list of the bonds in order of decreasing polarity? (ie, list the most polar bond first) A) C- H > O- H > N-H B)O OH>-CH>N-H C) N---H>OH>CH D) O-H-->NH>CH E) C-H-—>NH>OH Vii. Which of the following molecules has a conjugated pi system? 0 WCHS U/\ Q ® B c D A Name: Last, First (PLEASE PRINT) 2. Potpourri i. (2 pts each/8 total) Assign the missing formal charge for each of the following molecules: 4/ W M H3C-OH2 H3C—NH2 H3C—CH2 H3C—O; .1") A " ' fix ii. (6 pts) Consider the following pair of compounds (A and B) and circle which compound will have the highest boiling point. Briefly explain your answer. ®\VS' ©\NH2 Egmvl'Va/Pni/J _ M ‘fflci S (away-AX A / B LL/lli [9,6 c£,0h/U/lai—sz b4” . «ital divt‘geifl [Viv/clued M le/mxaulj lib? N) " TED/"64 “MW“? _ ' . .. - ,, o \m y’l IV\ / , / (Lu/l4”? drum “'3“ m ( ) y” . 64’ 3M rjfl V ‘y‘ l. . . . . ‘4/boy’l 1V5 Ifi .‘ ~ ’L‘LW 111. (4 pts Given. Cis-l,4-d1chlorocyclohexane. \1 +1444) .17 I 77 140 r Draw the correct conformation after a ring flip. You must maintain the e act carbon H positions as shown in the original structure. , ng/ ‘ ‘ Jr" ‘1 via a J‘“ "F“ ‘}\v V \ . i4 / Cl Z :7 7 “‘fl 41v U c4 ' L ,y » iv. (6 pts) Give the absolute configuration of the stereogenic centers in the following molecules: 0 I ' N, CHZOH 3 ' R or s {L Cll/I CH3 L" - ”W K <3 1 CHZCH3 3 \ ~ ‘= R or S Name: __ Last, First (PLEASE PRINT) 3. (14 pts) The following statement may apply to SNl, 5N2, El, E2 or none of these types of reactions. Next to each statement write the correct type of reaction. Write “NONE” if the statement does not apply to any of these reactions. More than one answer ma be re uired for each statement. Write all correct answers in the box. [Extra incorrect a ill result in points being taken away] ”:XVO _- 'lfllbfl/ W _ L r. g, l! A. Reaction in which a tertiary alkyl halide reacts slower than a primary alkyl halide , ##ha ‘ U / hail/I 494/ /LLM,r . @1944 5' ‘Iflfl/L Pr) 147 gay (bay/(j h «(,1 064‘, B. Reaction in which a stereogenic (chiral) center undergoes . . I racemizatlon (’a ADC (05? [Mun/«Walk . 9 I SW C. Substitution reaction in which the type of nucleophile does not affect the rate of the reaction 2“} \. \_. D. Reaction that applies to the following equation 3— §/\/ / Cl 0 + /ll\ ——-—> + HCI O. E. Reaction in which the overall reaction occurs in one step SN'Q/ E 2, F. Reaction in which both a proton and a halide ion are lost in the rate determining step from the alkyl halide G. Reaction in which a carbocation is formed as an intermediate C , / F: / Name: Last, First (PLEASE PRINT) 4. (27 p15) Reactions of the Organic Variety Write the structure of the major organic reactant or product in the BOX that would complete the following reactions. BE SURE TO SHOW ALL STEREOCHEMISTRY. IF NO REACTION OCCURS WRITE “NO REACTION. CH3CH20H L45 Name: Last, First (PLEASE PRINT) 5. (8 pts) Sugar is sweet The most stable form of glucose (blood sugar) is a six—membered ring in a chair conformation with its five substituents in the equatorial positions. Draw the most stable form of glucose, illustrating the position of the —OH, and —CH20H substituents in the chair conformation. CH2OH /_ 125 My, “)1, HO DA W3 M o 4' , glad/u, HO OH \ P ”35(4) WI > OH "3 a glucose //7~,/ {in [“037 WM]??? 6. (6 pts) Example structures of the major components of gasoline, diesel and biodiesel are shown below. Indicate which will have the highest boilingpoz'nt and briefly explain your answer: ’ ”a ‘\ W “3‘3 3 CH3 H3CH2co 3 9350""9 (octane, C8H18) diesel (dodecane, C12H26) biodiesel (C12H2402) le' I‘M m ‘V’ haw de/Méb/ 0““ fl) wa/i/ Z I“) ~ ”(kg/Ar, [Lab/WV hog/LL CD17 3 a f3 WC V Z ((17 _ , [Iii/)LL/C/L " (>0 1/ //WM‘ h/MI/ f} it _/ “dd/47 flW p7,“; ‘ a l V77“, 54,61," [(1/4 (VIM , l / 7. (5 pts) Adenine and guanosine nucleosides of DNA have a nucleophile amine that. can react with electrophiles, leading to DNA mutations. If you compare the primary amine in DNA to a primary amine in cyclohexamine, which amine is more nucleophilic? Explain your answer. 0 //WN"‘~-g ((1: U H‘ B; 5 (WV/'1 IVLL T N/ NH2 NH2 \ 3k "i 1,, W, ,, . DNA \ / D , 3 ,4 ‘44,: (A- , 3 3‘ T I l3 ”bl; 5/, LL*’L (3’ng O // , . \ / V/ / )U » )\N P3 5 ’ ,, l g a (dot JUL/xv 1’" MAE} 3., . ' ’ 2/ A (A CMDPLH 3' C Name: __ Last, First (PLEASE PRINT) 8. (20 pts) Consider the acidity constants below to answer the following questions: Acid Structure 1&1 phenol OH 10.0 16.00 ethanol /\OH ’/,,~~-=\ water H20 1574 // pl” l“ 0L a) Draw the Lewis Dot structure for the conjugate base of Ethanol (Show all lone pairs and ‘ indicate any nonzero formal charges on the molecule). )4 ‘\_,, a (4 '4 A ll " é (i x u awc-w / {J .5 Giff/7 ./\"f‘; i I " Mm a 4 I ' , x) H “l . 1* ’ ’ Z 0“, b) Which acid above will be almost completely deprotonated by NaOH? Q3 N” on” can; \ ’PMHOl / w M .Jb mo c) Which acid has the strongest conjugate base?? @ QMAHDI electron movement. ‘ \ %( “blame I S ‘(iLL "‘ - ‘ ’ k V { “1 . 61/ EN Wei MW 9,10%? “Pl QM, 04M] “[1,, ba,.u,,, g+y l’ ['4‘ l) 1/ S _ i, , Lira-‘1 ~‘ _ , it t 1149’” W l g S’ffl l!) (43/ W €WW f? Name: __ Last, First (PLEASE PRINT) 9. (22 pts) The antidepressant fluoxetine, sold under the trade name of Prozac, can be prepared by a substitution reaction of an alkyl chloride (A) with a phenol (B) using a weak base to generate the phenoxide anion. Cl CF3 C CH3 N/ weak base + ———> 0 CH3 / F3 CH3 / A N\ CH3 0 H B more steps UCFS 0 CH3 / .y; N\H , \‘xvi ‘ Prozac @l i. Label the chiral center @bove with an asterisk. ii. Draw the structure of the nucleo hile in this reaction. " ‘ n p GOA/OVLM [1' CM ,_—. % bm‘WWW‘VW § W0! +0 W“ ”i "‘5‘. Q P 0%er iii. If the rate of the reaction depends on the concentrations of both A and B, is this an 5N2 , or SNl reaction? iv. If the reaction proceeds by an 8N2 mechanism, and the starting alkyl halide £13, draw the chemical structure of the Prozac ultimately produced and identify it as 6r S. EM up w} ‘3 o/@4a3 @ \ .3 ' /C/H§ Eiww v. If a strong base is used initially in the reaction of A and B instead of a weak base, less desired ether is formed. In fact, an undesired product is formed that is reacts with Hz/Pd catalyst. What is the structure of the undesired product? [a Eliml‘na‘fiufl WDVDOUM} \‘S [Andi/18)»?ai “PWK/{Mcj’ U w ; \ , / 3 /‘\ LEN V43 8 Name: Last, First 9101“ (PLEASE PRINT) 10 (10 pts) Chemistry Rodeo- Do all molecules really look alike? Circle (lasso) the molecule that best answers the question. mompound 1s the weakest acid (i e. mosstH difficult to remove a proton from)? B. Which compound ' (are) chiroazl? [email protected] C. Compound with the highest boiling point? /\/OH /\/0\ /\/SH N D. Compound that would be most reactive in an SN 2 Reaction. CI Cl C . E. Compound that would be the least reactive in an 8N2 Reaction. [email protected] Name: Last, First (PLEASE PRINT) 1 l. (20 pts) Consider the Williamson Ether synthesis, as illustrated below: 1. Na 0 OH ________, \CH3 2. CH3I a. Draw the mechanism of the two steps of this reaction, using arrows to show electron b. Mechanistically, the second step of the Williamson ether synthesis out med above is what type of reaction?? ’ 3W) 50 ‘3‘ c. Suggest an alternative alkyl halide and alcohol as starting materials in the Williamson Ether synthesis to make i _e same ether product. [3 0MB”; 1“ x ./W ______ _ flflflflflfl :MMFMMW .. .. .- a, \ 4 ' /7°“ + UlgB" ’9' \ W5 \./ ~HM> Me ya fig“; itmr Would th alternative approach you suggested above be better or w se than the a l 613‘ng original synthesis? Why? Name: Last, First (PLEASE PRINT) 12. (8 pts) Biological Substitution reactions. The reaction of S-adenosylmethionine (SAM) with Norepinephrine is an example of an 5N2 reaction that occurs in living organisms. Given the structures of norepinephrine and SAM below, show with arrows how the 3N2 reaction occurs, and the resulting products that are formed. Norephinephrine is the nucleophile in this 8N2 reaction, with the nucleophilic amine highlighted in bold. l); NH2 N \ OH HOOC N HO it 7 / NH2 HzN N OH OH Norepinephrin S-adenosylmethionine X \ o ‘4 ll Name: Last, First (PLEASE PRINT) l3. (8 pts) The following compound has four stereoisomers: CH3CH=CHCHCH3 OH Draw and label with appropriate names all four stereoisomers. . l l Cl ’ '- 1! I (I . CH u. U a 1 (#290, C,““ ’4 Hgkc...‘ C/ ‘5 \ at“ C/ 5914 IV/ KL‘:L,E / i \ ”a C/ km W9 \ /‘ f \ / \ C "‘ / H C p, H CH5 / \ % 1+ H a .5 1 ' \w L: L Mime/ “\fi» "A“ M C I S ,- 87—min" a} ”(Ila/ZhDV’UEr) 2 (){fltm hmwzs 14. (10 pts) Indicate the reagents needed to carry— out the following syntheses with the central alkyne: d \/\ E \ V ,/D I C \/\ Br B A. HA Pd new ("mix/SJ“ 8‘ Pr" (‘wv/Ilmmg/H‘po C- 51 £2 LuVCvuwr’a HBI‘ . 12 Name: Last, First (PLEASE PRINT) 15. (8 pts) 3—bromocyclohexene undergoes an El reaction more readily than ane. Explain using chemical structures and features of the E1 mechanism. buyer-«2, ”Br—[Moaptolwxqma /r\ CW L949 J; \__ ill? hfigflflwxc / H , - Mtyii L / Lg? bromocyclohex 2 Al) mm 0 “Ida §+g Ail/<35; 730%.. 0 f {has} ENE? + (QM/0(ah‘71/ H , t . "‘ - . ‘ / M (fiM~ 5231“ I} H“ is 970%th XU’QI 6‘ ?"' [u ‘ saw/Lei- i \.\ /E/\\ l K C 16. (10 pts) Consider the following reaction: A B CD; a) Draw a reaction coordinate diagram in which C is the most stable and B is the least stable of the three species, and the transition state oing from A to B is more stable than the transition (3? b) How many intermediates are there? i C7 0) How many transition states are there ($6 A976 .. / ’ d) Which step is the fastest in the forward direction? ,/ "W e) Which step is the rate—determining step? [5 i; C, 13 ...
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