Exam 2 2009 archives key

Exam 2 2009 archives key - CHEM 3311-200 Exam 2 Fall 2008...

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Unformatted text preview: CHEM 3311-200 Exam 2 Fall 2008 By printing my name below, I pledge that “On my honor, as a University of Colorado at Boulder student, I have neither given nor received unauthorized assistance on this work." Name Student CU ID # NOTE: Exams will be returned by your TA in recitation! Recitation TA's Name I (Bailey, Meylemans) Recitation Day (it Time Grading Information Page # Points Possible Your Score 2 (Questions 1 :5: 2) 20 m 3 (Question 3) 12 __ 4 (Questions 4 6i 5) 24 _ 5 (Question 6) 22 m 6 (Questions 7 a 8) 22 w TOTAL (out of 100) General Instructions (1) This is a CLOSED BOOK exam! No notes and molecular models are allowed. (2) You have 2 hours to complete the exam. (3) Write your name at the top of each page, starting with page 2. (4) Use the back of exam pages for scratch paper. (5) Cell phones must be turned off: cell phones, headsets, and Bluetooth devices must be placed in a backpack or on the floor, and may not be accessed during the exam. Students violating this policy will be asked to leave and will receive a zero for the exam. (6) If caught cheating, you will receive at best an F for this exam. The instrUCtor reserves the right to proceed further, in compliance with university policies. Name: #VLS'V‘fi/L 1. (10 poinTs) WriTe bond-line sTrucTural formulas for ALL The consTiTaTionally isomeric alcohols of molecular formula C4H100. Assign an IUPAC name To each isomer uséng eiTher The subsTiTuTive or funcTionaE class sysTem of nomenclaTure. Please enTer The informa‘rian in The spaces provided. The number of rows may noT necessarily correspond To The maximum number of alcohols buT provides guidelines To faciliTaTe grading. CW, We; _{ficg0151;b 4‘ 61/ 2/» ) Bond-line sTrucTural formula IUPAC name OH OH . 2 2. (10 poirrrs) WriTe a clear, legible, sTepwiSe mechanism for The reacTion of meThanol wiTh hydrobromic acid. Label each sTep as STep 1, STep 2, eTc. and indicaTe wheTher it is a slow or fasT 392. For The slow sTep, label The mechanism as 5N1, 5N2, E1 or E2. Please show ALL lone pairs, formal charges, and The arrow—pushing mechanism. .. O H /o' e H H H H ' l at H / [.0 \H . H H 2 sfe 5 : SE}: 1 Maj AWC’é'M’t‘L pf 05‘. + - G) H HZO:-/m—‘3’L w H30 + i l H jaw—t H H 2 “‘2: [email protected]/ H + Hzé' H L H/ flu Name: #"SWQ’L 3. (12 goinTs) IdenTify The relaTionship in each of The following pairs as consTiTuTional isomers, enanTiomers, diasTereomers, or idenTical (differenT ways of drawing The same compound). Wr'iTe your answer on The line for each pair. (A) Ow and ole/ltd v“. HZOH HZOH COOH (3) COOH H A r d H Br H Br cm trumfi/oem H Br CH 3 I_I3 (C) OH CH3 HO\ H H30 ’4’ and §~ CHZOH HO H :3 \ CHZOH H0 H (D) $HO CHO HO H . and H OH ,BMM/tA’I/W CHZOH CHgoH Name: We» 4. (12 poinTs) Consider The gas-phaSe reacTion of eThane wiTh chlorine aT high TemperaTures (420°C). Show The deTailed mechanism for The propagaTion steps in The formaTion of chloroeThane. Please wriTe each sTep in The recTangular box provided. The number of boxes shown has no relaTion To The number of steps. Please show all lone pairs or unpaired elecTrons and The appropriaTe arrows CLEARLY. 5. (12 poin’rs) IdenTh‘y each compound as achiral, chiral, and/or meso by circling The correcT Iabel(s) lisTed below each compound. [)0 NOT circle labels ThaT are NOT relevanT To The molecule shown (poinTs will be deducted). c0211 ' CH3 @ achiral achiral chiral chiral meso mesa meso Name: 6. (22 goin‘rs) Draw The s‘rr'uci'ur'e of The major producfls) of each reaction. Circle The mechanism The? uccounTs for' The formafion of This product Circle The mechanism NGOC2H5 _,__ E1 S 1 S 2 KOC CH (B) CH3I —n—flp (CH3)3COH OTs KCN 9H ' (D) fix ___ E1 132 SN1 ® H e’r hanoi-wai'er CN mam-13)3 (E) r' W W M E1 @ 3N1 3N2 NGOCZH5 (F) (CH3)2CH«I ———- CZH5OH, 55°C “.52.. ‘u- _; . a n. Name: ' 7. (12 points) Draw the correct stereochemistry of the product(s) for each reaction and specify, where necessary, whether you obtain equal or unequal amounts of enantiomers or diastereomers. Br ,li ht /Y\/ 2 g i W 4- />9/\/ '1 . . I (monobronnnation) ’CBA 33h 5’ . . . enantiomers or diastereomers Circle one answer In each row of chalces gequal amounts unequal amounts ' ‘9 : \\\ . ' ‘\ />/\/ BIZ, fight w 1" AX/ _"""—"““——"' 4,, ., / 9,0 02 (monobrominatj on) C1 . . . enentiomers a diastereomers Circle one answer 111 each row of choices . equal amounts unequal amounts H20 —---—---———>- 4. ethanol NW Br 0H 6H . ' . . enantiomer or diastereomcrs Clrcle one anSWer In each row of chmces equal amoun unequal amounts 8. {10 points) When (S)-2-chloropentane is reacted with lithium diethylcopper under 5N2 conditions, an opticaily Eyre 3-methylhexane is formed. The nucleaphile is the ethyi carbanion. Complete the reaction shown below by placing the information requested in the appropriate boxes. Circle the absolute configuration at the stereogenic center in the produat of the reaction. , H3(./\CH2CH2CH3 (5)- 2-Chloropentane + —> ( )— 3 - Methyihexane Place the appropriate atom ofgroup of atoms (opfically pure) in each box to complete the structure of Place the appropriate atom oflgroup of (S)-2—Chloropentane atoms in each box to complete the structure of optically pure (?)-3- Methylhexane The absolute configuration at the chiral carbon in the optically pure (?)-3-Methylhexane is: R (5) Ci cle the orre answer ...
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Exam 2 2009 archives key - CHEM 3311-200 Exam 2 Fall 2008...

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