Ch328n Xm1 Key Colapret

LAST NAME: FIRST NAME:

UTEID: COVER PAGE

Instructions This exam will be closed book. No notes, books, calculators, or molecular models will be allowed. The exam will be comprised of two distinct parts: Part I will consist of a series of multiple choice questions. Your answers to these questions must be submitted on a Scantron bubble sheet. The answer sheet will be provided for you, but you will need your own #2 pencil(s). Only answers marked on the bubble sheet will be graded. Answers to Part I questions marked on the exam itself cannot not be graded. No re-grades will be possible on Part I of the exam. Part II consists of questions for which you will need to write out your answers, using structures and/or words. This part of the exam will be hand-graded. Answers for the Part II questions that are written in pencil will not be eligible for re-grades. Answers written in pencil with ink overlay will not be eligible for re-grades. If you use a pen to answer the Part II questions, only blue or black ink is acceptable. Answers written in red ink cannot be graded.

1. You must have your valid UT ID card (or other government-issued ID) with you. You will need to show it to the proctors when you turn in your exam.

2. Chapter 4 of the Universitys General Information catalog outlines this universitys policies regarding exams, as well as other quizzes administered during the semester. Specifically, students are expected to remain in the exam room until a test is completed. These policies will be strictly enforced, with no exceptions. You may not leave the room for any reason until you are ready to turn in your exam. If you wish to leave the room, you will need to turn in your exam to the proctors, and you will not be allowed to return. Please, plan accordingly by using the rest room before the exam starts.

CH 328 N Exam I

Question Value Score 1 10 2 20 3 15 4 15 5 15 6 15

Section II 90

Section I 60 Raw Total 150

Grade

UTID: ________________________ September 2013

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CH 328N-Exam 1

Objective SectionIdentify the choice that best completes the statement or answers the question. Only one choice is correct; be sure to carefully bubble your answer on the scantron sheet. (4 pts ea.; 60 pts this section)

1. What is the x-axis of a mass spectrum?a. mass/energyb. mass/chargec. charged. mass

2. Which C4H9Br compound gives a triplet at approximately 3.5 ppm in the 1H NMR spectrum?

a. 1b. 2c. 3d. 4

3. What is the hydrogen deficiency index for a compound with a molecular formula of C10H16O2?a. 1b. 2c. 3d. 4

4. Which feature in the 1H NMR spectrum provides information about the relative number of each type of proton in a compound?a. number of signalsb. splittingc. chemical shiftd. integral

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5. What reactive intermediates are involved in the following reaction?

a. the trichloromethyl anion (Cl3C: ) and dichlorocarbene (Cl2C:)b. the cyclohexyl carbocationc. the cyclic chloronium ion derived from cyclohexened. the trichloromethyl cation (Cl3C+)

6. Which of the following processes takes place upon absorption of infrared radiation?a. electron spin flipb. bond vibrationc. electron excitationd. nuclear spin flip

7. Which feature in the 1H NMR spectrum provides information about the number of neighboring protons of each proton in the compound?a. integralb. chemical shiftc. multiplicityd. number of signals

8. Which of the following sets of molecular ions does an alkyl bromide possess?

a. two molecular ions in a 1:1 ratio separated by two mass unitsb. two molecular ions in a 3:1 ratio separated by two mass unitsc. three molecular ions in a 1:2:1 ratio separated by two mass unitsd. two molecular ions in a 2:1 ratio separated by two mass units

9. Which of the following bonds has the most ionic character?a. CHgb. CAlc. CMgd. CZn

10. Which of the following sets of molecular ions does an alkyl chloride possess?

a. two molecular ions in a 3:1 ratio separated by two mass unitsb. two molecular ions in a 1:1 ratio separated by two mass unitsc. three molecular ions in a 1:2:1 ratio separated by two mass unitsd. two molecular ions in a 2:1 ratio separated by two mass units

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11. Which of the following compounds gives an infrared spectrum with peaks at 3000-3500 cm1 and ~1750 cm1?

a. 1b. 2c. 3d. 4

12. Which of the following bonds gives rise to a strong, broad, absorbance at approximately 3200-3650 cm 1 in the infrared spectrum?a. C=Ob. CHc. C=Cd. OH

13. What is the y-axis of a mass spectrum?a. abundanceb. field strengthc. massd. energy

14. Which of the following alcohols can be prepared from a Grignard reagent and ethylene oxide?

a. only 1b. only 1 and 2c. only 1, 2 and 3d. 1, 2, 3 and 4

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15. What is the major organic product obtained from the following reaction?

a. 1b. 2c. 3d. 4

ID: A

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CH 328N-Exam 1Answer Section

MULTIPLE CHOICE

1. ANS: B PTS: 4 2. ANS: A PTS: 4 3. ANS: C PTS: 4 4. ANS: D PTS: 4 5. ANS: A PTS: 4 6. ANS: B PTS: 4 7. ANS: C PTS: 4 8. ANS: A PTS: 4 9. ANS: C PTS: 4 10. ANS: A PTS: 4 11. ANS: C PTS: 4 12. ANS: D PTS: 4 13. ANS: A PTS: 4 14. ANS: B PTS: 4 15. ANS: A PTS: 4

CH 328 N EXAM #1 UTEID

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KEY PART 2: Free Style Answer Format (90 pts in this section)

1) There are four constitutional isomers of dichloropropane. The NMRs of 3 of these are shown below. Match each isomer with its NMR and provide an interpretation of each spectrum. (i.e. draw the structure on the NMR and label protons, with their splitting.) (10 pts)

0123PPM

H3CC

CH3

Cl Cl

a a

a, singlet

01234PPM

2

4 ClCH2

H2C

CH2

Cl

a, tripleta, tripleta

b, pentet

b


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KEY

2) Provide either the reagents or the product(s) for the following reactions. This is not a mechanism question-simply write the answers in the boxes. (5 pts per structure)

O 1) PhMgBr

2) HCl/H2O

OH

Ph

H

O 1) CH3CH2CH2Li

2) HCl/H2O

OH

CH2I2; ZnCu

Cl CH2

C CH2

CH3 CH3

H3C

2CuLi


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KEY Unknowns: The molecular formula, IR & NMR are provided for the following unknown compounds. For each problem, provide the structural information from the IR & NMR and propose a structure for the unknown.

3) Unknown 1 (the compound has a formula of C5H12O)

IR indicates (just provide the functional group(s):

Draw the structure & label the protons using the a,b,c labeling method.


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KEY

4) Unknown 2 (the compound has a formula of C4H8O2)


See next page for expanded NMR of Unknown 2


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KEY Unknown 2: expanded NMR


12 peaks


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KEY

5) Unknown 3 (the compound has a formula of C6H12O2)




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KEY

6) Unknown 4 (the compound has a formula of C5H11Br)



END OF EXAM SECTION

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Ch328n Xm1 Key Colapret