TERNANSKY Midterm 1+2

TERNANSKY Midterm - Chemistry 140A Fall 2006 First Midterm Exam-250 points DO NOT OPEN THIS EXAM UNTIL INSTRUCTED TO DO SO.FILL OUT THE FOLLOWING

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Unformatted text preview: Chemistry 140A Fall, 2006 First Midterm Exam-250 points 10/17/06 DO NOT OPEN THIS EXAM UNTIL INSTRUCTED TO DO SO.....FILL OUT THE FOLLOWING INFORMATION NOW : . YOUR NAME (Print): Ima Key . SIGNATURE: . ID checker initials: . If you wish to have any answers considered for a re-grade, your exam must be completed in INK . 1. (22 points) Draw the Lewis dot structure for THREE resonance contributors of the molecule shown . Use electron-pushing arrows to indicate how the resonance structures are related to each other. Be sure to draw all valence electrons and clearly indicate charges where appropriate. Use straight lines for bonds and dots for valence electrons. (That is, use Kekule drawing) When choosing resonance contributors to record as your answer, choose ones such that ALL structures you draw satisfy the octet for all appropriate atoms. (-)CH 2 NO 2 C N O O H (-) (-) (+) H C N O O H H C N O O H H (-) (-) (+) (-) (-) (+) BEST 6 points each correct structure (18 total) 2 points for double-headed arrows 2 points for brackets 2. (8 points) Circle the best resonance contributor above. Give the reason for selection of this as the best resonance contributor: NEGATIVE CHARGE LOCATED ON OXYGEN RATHER THAN CARBON 4 points to identify the best contributor 4 points for correct reason 3. Consider the following compound for answering the next questions: O O H 2 N OH H H *H 1 2 3 4 5 6 • (3pts) Write the molecular formula for this molecule C 10 H 13 NO 3 • (9 pts) Classify carbons #3, #4 and #5 as primary, secondary or tertiary: #3 : tertiary #4 : secondary #5 : tertiary • (6 pts) Write the total number of sigma bonds in the molecule: Sigma bonds: 29 • (3 pts) How many rings are present in the molecule? Total number of rings: THREE • (6 pts) How many atoms in this molecule are hybridized sp 2 ? Total number of sp 2 atoms: FOUR • (3 pts) The –OH group attached to which face of the molecule? ALPHA • (4 points) What is the special name given to carbons #2 and #5? BRIDGEHEAD • (12 pts) Name all the functional groups present in the molecule. Do not include “alkane” as a functional group (minus two points for each incorrect name): AMIDE ETHER ALCOHOL ALKENE 3 points each correct name; minus 2 points each incorrect name • (3 pts) How many lone pairs of electrons are present on the molecule? SEVEN • (3 pts) Is carbon #4 considered to be a methyl, methylene or methine carbon (circle answer)? • (5 points) The bond connecting the H* with the carbon #1 is made up of the overlap of two orbitals. What are the two orbitals that overlap to form the bond? sp 2 and s 4. (10 points) Rank the pKa values for the following compounds: OH F OH Br OH CN OH 1 2 3 4 A) 1>2>3>4 B) 2>3>4>1 C) 3>4>1>2 D) 4>1>2>3 E) 1>3>4>2 F) 2>4>1>3 G) 3>1>2>4 H) 4>2>3>1 I) 1>4>2>3 J) 2>1>3>4 K) 3>2>4>1 L) 4>3>1>2 M) 4>3>2>1 N) 3>2>1>4 O) 2>1>4>3 P) 1>4>3>2 5. (14 points) Name the following molecule according to the IUPAC system of nomenclature. DO NOT use trivial nomenclature (NO partial credit for names):...
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This note was uploaded on 10/30/2008 for the course CHEM 140A taught by Professor Whiteshell during the Spring '04 term at UCSD.

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TERNANSKY Midterm - Chemistry 140A Fall 2006 First Midterm Exam-250 points DO NOT OPEN THIS EXAM UNTIL INSTRUCTED TO DO SO.FILL OUT THE FOLLOWING

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