Study Guides (380,000)
US (220,000)
CU-Boulder (1,000)
CHEM (10)
All (10)
Midterm

chem_3351_first_hour_exam_key_fall_2015Exam


Department
Chemistry & Biochemistry
Course Code
CHEM 3351
Professor
All
Study Guide
Midterm

This preview shows pages 1-2. to view the full 8 pages of the document.
Easily Legible Printed Name:______________________________
Page 1 of 8
CHEM 3351 (100), Fall 2015
Professor Walba
First Hour Exam
September 22, 2015
scores:
1) 20
2) 20
3) 20
4) 20
5) 20
100
PLEASE read the questions very carefully!
PLEASE legibly print your name on each page of the exam.
H
He
Li
Be
B
C
N
O
F
Na
Mg
Al
Si
P
S
Ne
Cl
Ar
Br
I
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
35
53
1A
2A
3A
4A
5A
6A
7A
8A
CU Honor Code Pledge: On my honor, as a University of
Colorado at Boulder Student, I have neither given nor received
unauthorized assistance.
Signature: ______________________________________
Recitation TA Name: _____________________________
Recitation day and time: ___________________________
This is a closed-book exam. The use of notes, calculators, scratch
paper, or cell phones will not be allowed during the exam. You
may use models brought in a clear Ziploc bag. Please put all your
answers on the test in the appropriate place. Use the backs of the
pages for scratch (there are two additional blank scratch sheets
after the last page of the exam). DO NOT PUT ANSWERS ON
THE SCRATCH SHEETS.
Key

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Printed Name:
Page 2 of 8 Total points for this page:
1 (20 pts) a) For 2,4-dimethylpentane (structure shown at right), let the eclipsed
conformation shown in the Newman projection on the energy diagram below be
defined as the 0° dihedral angle.
Draw Newman projections of the three staggered conformations of 2,4-
dimethylpentane sighting down the C2-C3 bond, in the boxes. Please rotate the
front carbon clockwise moving from 0° to 60°, 180°, and 300°.
Complete the energy diagram by indicating the relative energy of all the conformations (eclipsed, staggered,
and everything in between) in the rotation from 0° to 360° = 0° using a smooth curve.
2
3
You're Reading a Preview

Unlock to view full version

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Printed Name:
Page 3 of 8 Total points for this page:
1– continued
b) Give the degree of substitution (1°, 2°, 3°, or 4°) for carbons 1 – 5 (the main chain) of 2,4-dimethylpentane.
1 2 3 4 5
c) Draw skeletal structures (molecular graphs NOT showing the hydrogens) of all possible isomers (constitutional
isomers and stereoisomers) for hydrocarbons with the molecular formula C4H8. Draw each isomer only once. Points will
be deducted for missing structures, and for drawing the same structure more than once.
1
2
3
4
5
You're Reading a Preview

Unlock to view full version