Chemistry 310M/318MDr. Brent Iverson1st MidtermSeptember 30, 2010

NAME (Print): _____________________________

SIGNATURE: _____________________________

Please Note: This test may be a bit long, but there is a reason. I would like to give you a lot of little questions, so you can find ones you can answer and show me what you know, rather than just a few questions that may be testing the one thing you forgot. I recommend you look the exam over and answer the questions you are sure of first, then go back and try to figure out the rest. Also make sure to look at the point totals on the questions as a guide to help budget your time.

Please print the first three letters of your last name in the three boxes

You must have your answers written in PERMANENT ink if you want a regrade!!!! This means no test written in pencil or ERASABLE INK will be regraded.

Please note: We routinely xerox a number of exams following initial grading to guard against receiving altered answers during the regrading process.

FINALLY, DUE TO SOME UNFORTUNATE RECENT INCIDENCTS YOU ARE NOT ALLOWED TO INTERACT WITH YOUR CELL PHONE IN ANY WAY. IF YOU TOUCH YOUR CELL PHONE DURING THE EXAM YOU WILL GET A "0" NO MATTER WHAT YOU ARE DOING WITH THE PHONE. PUT IT AWAY AND LEAVE IT THERE!!!

Honor Code

The core values of the University of Texas at Austin are learning, discovery, freedom, leadership, individual opportunity, and responsibility. Each member of the University is expected to uphold these values through integrity, honesty, trust, fairness, and respect toward peers and community.

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1. (4 points) What is the most important question in Organic Chemistry?

2. (8 pts each) For the following molecular formula, draw complete Lewis line structures in which all atoms (even H atoms) are drawn, lines are used as bonds, all lone pairs are drawn AND ALL FORMAL CHARGES ARE INDICATED.

1) (CH3)CCH2OCH2CH2NH3

2) H2NCHOHCO2

How many different stereoisomers are there for the above molecule?

How many different stereoisomers are there for the above molecule?

(You only need to draw one of the major contributing structures)

Pg 2 _____________(22)Signature_________________________

3. Provide an acceptable IUPAC name for the following molecules. You can ignore R and S for this one.

A) (6 pts)

C

CH3

CH3

CH2 CH2CH2 CH CH2 CH2CH2H3C

B) (6 pts)

C) (10 pts) H3C

CH3

CH3

CH2CH3C CH3

CH3

CH3

Although stereochemistry is not indicated on the above structure, how many stereoisomers are possible?

Although stereochemistry is not indicated on the above structure, how many stereoisomers are possible?

Is the molecule chiral? If you answered yes, then in the box provided, draw the enantiomer of the above structure.

Pg 3 _____________(15)Signature_________________________

5. (5pts each) For the following IUPAC names, draw the appropriate line angle drawing (you can ignore R and S for this).

A) 4-tert-butyl -5-ethyl-2-methylheptane

B) trans-1-methyl-3-(1-methylethyl)cyclopentane

C) (Challenge!!) R-5-isobutyl-2-methylnonane (Use wedges and dashes to indicate the appropriate stereochemistry)

Pg 4 _____________(20)Signature_________________________

6. (5pts each) The following molecules are best represented as the hybrid of contributing structures. Draw the second important contributing structure in the space provided, including all lone pairs and formal charges. For the structure on the left, use arrows to indicate the movement of electrons to give the structure you drew. Finally, if one of the two contributing structures makes a dominant (major) contribution to the resonance hybrid, draw a circle around the dominant (major) contributor. You might want to read these directions again to make sure you know what we want.

A.

CH

H

H

CO

O

B.

C.

C NH

HN

D.

HC

CC

H

H

HH

CH

H

H

CC

O

HH

Pg 5 _____________(20)Signature_________________________

7. (10 pts each) The following molecules are best represented as the hybrid of three contributing structures. Draw the second and third important contributing structures in the spaces provided, including all lone pairs and formal charges. For the two structures on the left in each problem, use arrows to indicate the movement of electrons to give the structures you drew. There is no need to draw any circles around any of these contributing strucures. You might want to read these directions again to make sure you know what we want.

A.

O CO

O

B.

C NO

O

H

H

OORibbit

Pg 6 _____________(31)Signature_________________________

8. (2 pts each) Fill in each blank with the word or words that best completes the sentences.

For organic chemistry, it is best to think of electrons as __________________.

According to the ________________________________ approach, the atomic orbitals on each atom

are combined (hybridized) first, and bonds are derived from overlap of hybridized orbitals.

It is best to think about all ____________________ bonding in molecules as being derived from the

overlap of hybridized orbitals and all __________________bonding as being derived from overlap

of unhybridized 2p orbitals.

9. (1 pt each) For the following molecules, write the hybridization state of each atom indicated by the arrow.

O

N

CC

CH

O

H

HH

In solution, alkane molecules are weakly attracted to each other due to___________________________

forces, which are the weakest of the electrostatic interactions (i.e. charge-charge interactions) and

are the result of attraction between _________________________ (induced) dipoles among adjacent

molecules.

CH

H H

N

N

H

CH3

Nicotine

O O

OO

NHH

HNa

MSG

Pg 7 _____________(32)Signature_________________________

9. (2 pts each) Describe each bond indicated with an arrow as the overlap of orbitals. For example, an

answer might be σCsp3-Csp3.

O

O

H

CH3

H3C

CH3

Ibuprofin

N

N

N

O

CH3

H

LSD

NH3C C

OMethyl

Isocyanate(the molecule that cuased the Bhopal tragedy in India in

1984)

Pg 8 _____________(22)Signature_________________________

10. (3 pts each) For the following molecules, use the dipole moment symbol to show the direction of the molecular dipole moment in all molecules that have an overall molecular dipole.

Cl

CH

HH

H

CCl

ClClH

CC

CH

O O

H H

For the moleculeabove list the molecular dipole for the

conformation shown.

11. (10 pts each) The following molecule is best represented as the hybrid of three contributing structures. Draw the second and third important contributing structures in the spaces provided, including all lone pairs and formal charges. For the two structures on the left use arrows to indicate the movement of electrons to give the structures you drew. There is no need to draw any circles around any of these contributing strucures. You might want to read these directions again to make sure you know what we want.

CHH

HCO

NH

H

CH

H

H

NO

O

Pg 9 _____________(14)Signature_________________________

12. (7 pts each) For the following cyclohexane derivatives, draw the two alternative chair conformations. If there is a difference in stability, draw a circle around the more stable conformation.

NH2

A)

B)

Pg 10 _____________(21)Signature_________________________

13. (7 pts) For the following molecule of glucose, draw both alternative chair conformations. Circle the one that is more stable. This is called α-D-glucose.

O OH

OH

OH

HO

HOH2C

14. (14 pts) For the following molecules, label each chiral center with an asterisk (*).

H3CCH3

OHH

H3C CH3

OHH

CO2H

CNH3H

H

CO2H

CNH3H3C

H

H3CCH3

Cl

Cl

Cl

CH3

CH3 CH3

CH3

CH3

Cl Br

HH

Cl Br

FH

HH

H

O

O "Andro"the steroid used by Mark McGwire and other sports stars

Pg 11 _____________(31)Signature_________________________

15. (3 pts) Label each chiral center as "R" or "S".

H3CC

H

Br Cl

H3CC

Br

H Cl

HC

Br

H3C Cl

H3CC

Cl

Br H

H3CCH3

H OHH3C H

16. (5 pts each) For the following conformations, draw the Newman Projection from the perspective indicated by the eye of the observer

CC

H

H3C

H3CH

CH3

Cl

CC

HH3C

HH3C CH3

Cl

CC

CH2SH

H CH3

O

HO

Pg 13 _____________(24)Signature_________________________

13. (4 pts each) For each pair of molecules, circle the one that has LESS STRAIN, then put an "X" in the box under the one or at most two types of strain that is/are most important to explain your answer:

Angle strain

Torsional strain

Steric strain

vs.H3C

CH3

vs.

CH3

HHCH2CH3

HHCH3

HHH

CH2CH3Hvs.

CC

H H

H HH H vs. CC

H

HH

H

HH

CC

H H

H3C CH3

H H vs. CC

H3C

HH

CH3

HH

vs. CC

H

HH3C

Br

HH

CC

H

HH3C

H

BrH

Pg 14 _____________(27)Signature_________________________

17. (27 pts) For each pair of molecules, on the line provided state whether they are (1) enantiomers, (2) diastereomers, (3) consitutional isomers,or (4) different conformations of the same molecule. Each pair of molecules will best be described by one of these four terms. Next draw a circle around all the molecules that would be optically active (i.e rotate the plane of plane polarized light), and write "MESO" under any meso compounds.

Relationship:

H3COH

H OH

H CH3

H3CCH3

HO H

HO H

H3COH

H OH

H CH3

H3CCH3

HO H

H OH

H3CCH3

H OH

H CH3

H3CCH3

HO H

H CH3

H3CCH3

H H

H HH

HH3C H

H CH3

CH3

C(CH3)3HH

CH3HCH3

C(CH3)3HH

HH3C

CH3

C(CH3)3HH

CH3HH

C(CH3)3H3CH

HH3C

Pg 15 _____________(15)Signature_________________________

20. (15 pts) Here is an "apply what you know" question. A series of alkanes are listed along with their boiling points.

A) From the data listed, draw two different conclusions regarding how boiling point changes with structure.

69° C

126°C

174°C

58°C108°C

160°C138°C

B) The boiling point of 2,2,3,3-tetramethylbutane is 106°C, in line with the other alkanes. However, 2,2,3,3-tetramethylbutane is a solid at room tempterature, not a liquid like the others, because it has a melting point of 104°C. It is only a liquid for the span of 2°C!! For comparison, octane is only a solid below -57°C. Briefly explain why 2,2,3,3-tetramethylbutane exhibits this unsual behavior.

Boiling point 106°CMelting Point 104°C

Boiling point 126°CMelting Point -57°C

Pg 16 _____________(20)Signature_________________________

21. (10 pts) Here is another "apply what you know" problem. If you get this correct, you will understand the basis for most of the chemistry in Chapter 16!! Remember the most important question in Chemistry! Shown below are the acetone molecule, a proton, and the hydroxide anion. Draw all the appropriate bond dipole moments on the acetone and hydroxide anion molecules for all the polar covalent bonds. Draw a BOX around the atom on the acetone molecule that is most likely to interact with the proton, and draw a CIRCLE around the atom on the acetone molecule most likely to interact with the hydroxide anion. Read these directions again to make sure you know what we want!

CH

H

H

C

O

C

H

H

H

O H H

Acetone

Hydroxideanion

22. (10 pts) Draw a circle around the following structures that represent molecules that are optically active when placed in solution. Draw a box around those structures that represent molecules that are not optically active when placed in solution.