322asu09_e2_key

322asu09_e2_key - CHEMISTRY 322aL EXAM NO 2 JUNE 8...

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Unformatted text preview: CHEMISTRY 322aL EXAM NO. 2 JUNE 8, 2009 (1) (20) __ (2) (15) __ (3) (10) ___ (4) (20) .____ Grader Please q” 2 Print L ast Name First Name Last 4 digits of USC ID XXXX-XX- TA Mimi G /_________4 first letter of last name I will observe all the rules of Academic Integrity while taking this exam. Signature Chemistry 322aL -2- Name Exam No. 2 (1) (20) Answer the questions below. (A) (12) Supply the requested information for each of the following reactions. Helpful information is available in the Appendix. Provide the structures of the products, as requested. Be careful to include counter-ions, where they are shown. In the shadow boxes, show the direction of the spontaneous reaction with an arrow. 3 “(A - q.) (i) CH3NH2 + HCl :: CH3N H3 + n M Mééx conjugate acid conjugate base + -H - Q o pKa = ‘7 conjugate acid conjugate base - —.__. (iii) cram-+1514+ + HCECH a... CHJQH3 + ’ conjugate acid conjugate base conjugate acid conjugate base (B) (3) Identify the Lewis acid and Lewis base in the reaction below and add any missing charges to the product immediately next to the atoms on which they reside. If 1 1 A, 93.x rH :' 19/ H CH3CHCH3 + MEL, 1 CH3CHCH3 L10 \ S B 35$ L1. ‘0 \ 3 El (supply any missing formal charge) (C) (5) For the reaction below, add all missing nonbonding electron pairs and all missing formal charges to the structures, and use the curved arrow formalism to show movement of an electron pair in forming the product. On the lines below the reactants, identify the nucleophile and electrophile in this reaction. ' @ CH3CH2CICZ-N: 5 CH3CH2 H + :CEN: Wi—Pbudw ‘M H Chemistry 322aL -3- Name Exam No. 2 (2) (15) Answer the following questions about nomenclature. (A) (6) Provide systematic (IUPAC) names for the two structures below. __ W3 @ HC=C-—CHZCHCH2C1 H3C s-cklgm-A—mg+\~3\-i~pg,d~m ‘5» H (B) (6) Provide detailed condensed structural formulas inside the oxes for the names below the boxes. 04 CH} 3 “CL cHg 1,3,3-trimethylcyclohexene ( 3) Provide a condensed structural @ formula for 2,2—dimethylbutyl bromide in the box to the right. (3) (10) Answer the questions below. H3 Cl\ H H CH3 Provide the IUPAC name of the above compound. @ 24mm mums Draw a Newman Projeaion Draw the most stable conformation of formula of the lowest energy tra -1-chloro-4-methylcyclohex conformation during rotation @ around the C2-C3 bond in buta What is the predicted amount of strain engy in the chair conformation of trans—1,3- dimethylcyclohexane in G units? A 3 "s - - \O fiflm\—° 0v. ‘3... m:.% \-3-C.\fLIOpQfi+2.-pol 0" I Chemistry 322aL -4- ame Exam No.2 1 : I (4) (20) Circle the correct answer for each question or statement below. (A) Which of the solvents below may not be used for the reaction: CH3C ECH + (i-PI')2N~ Li+ CH3C ~=C-Li + (i-Pr)2NH PKa ~25 pI<a ~33 CHSCHZOH C6H6 H20 CH3CHZOCH2CH3 (Circle answer below) ethyl alcohol benzene water diethyl ether 1! III In I II III IV I, II, IV only III (B) The order of acidity (strongest to weakest) of the bolded H in the structure below is (circle answer below) CH3CH2CH=CHCHZOH A>B>C B>A>C A) B) CJ C>A>B (C) According to the pKa values of their conjugate acids, the stronger base in each pair below is - — — — (circle answer below) CH CH O C H 0 (24—15803 (3611:4302 3 2 6 511 AI, BI AI, B II I _ pK . pKat 6.5 4.19 . a 16 99 A H, B H A B (D) In the biologically important hydrolysis reaction of adenosine triphosphate to adenosine diphosphate ATPS- + H20 ADPZ- + H2PO4- ' the standard free energy change is 116° = -7.2 kcal/mol, and the standard enthalpy change is AH° = -4.8 kcal/mol. Therefore, (circle correct statement below) -this reaction is not spontaneous with an energetically favorable entropy change. -this reaction is not 3 onta - u . «t IS reaction is sontaneous wi a . (E) The stronger acid in each pair below is CH3CH2COOH CH3CC12COOH CH3CF2COOH CH3CC12COOH I II I II A B (circle answer) A I, B I A I, B H A II, B I A II, B H Chemistry 322aL -5- Name Exam No. 2 2 ,m c k (4) Contd. (F) The constitutional isomer of C6H14 below that has only primary and tertiary H is (cir - elow) (G) In the two butane isomers below, - - 0nd with the largest barrier to rotation is (circle answer below) A/\5/ VC A C (H) Which conformation below is associated with the energy barrier of close to 10 kcal/mol observed during the inter-conversion of cyclohexane chair conf- u . tions? (circle answer) H O : 5 d (I) The Newman projection formula below of axial—methylcyclohexane that shows one gauche interaction is a View along which of the C-C bond axes (where the first carbon is in the foreground and the second carbon is in the background)? (circle answer below) H3 H3 CH H C-C CC 2 JJJJ2\ 12 21 ri C3.C2 5 6 1 H2 H H (J) Which of the conformational structures of 1,4-dimethylcyclohexane shown below is the most stable and is it the trans or cis diastereomer? CH CH H H CH3 I II III (circle answer) I cis II Cis ( II trans ) III trans Chemistry 322aL —6- Name Exam No. 2 (5) (10) The acid-base reaction shown below has a AG° = -7.9 kcal/mol, as written. AG° = -7.9 kcal/mol + CH3NH2 £A_ .13.. (A) (2) Will this reaction proceed spontaneously, as written? (yes or no) 1L3 H20 ’& (B) (2) On the lines below each reactant and product, identify the stronger acid (SA), stro er b e (SB), weaker acid (WA) and weaker base (WB). 4“ 01,0164 8 W (B) (4) Complete the free energy diagram below by correctly adding the starting state (with chemical structures) and the product state (with chemical structures) for the above reaction, and showing the direction of the above reaction (as it is written) with an arrow. Locate your states using the energy scale provided in the diagram. >5 9.40 c» C o) 3 4: :9 > '5 a ‘03 H (D)(2) Based on the above analysis, what is the likely structure of 3-arninopropionic acid in water? Draw the structure in the box below. HZNCHZCHZCOZH 3-aminopropionic acid Chemistry 322aL -7- Name Exam No. 2 (6) (10) Three isomeric alkynes (A,B,D), CSHB, are hydrogenated. Alkynes A and B yield the same alkane C. Alkyne D yields alkane E Based on the information provided, draw structural formulas for all five hydrocarbons inside the boxes. 1C CH3CH£HzC H A C5H8 B CsHs ir 3300 cm‘1 PKa "‘25 no ir at 3300 cm‘1 PKa > 40 9‘ excess H2 excess H2 L Pt CatalYSt 2 Q3 Pt catalyst “C b D l a symmetrical structure with 6 equiv 1°, 4 equiv 2°, and 2 equiv 2° excess H2 C H EH: C. H- C H Pt catalyst 2' 3 LHZ D C5H3 E (:5le ir 3300 cm'1 PKa ~25 an unsymmetrical structure with 6 equiv 1°, 3 equiv 1°‘ one 3° and 2 equiv 2° H ...
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This note was uploaded on 10/12/2009 for the course CHEM 322AL taught by Professor Jung during the Spring '07 term at USC.

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322asu09_e2_key - CHEMISTRY 322aL EXAM NO 2 JUNE 8...

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