Summer 2021 CHEM 211/212: MIDTERM assignment
1. (15 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
a. 10 points
Draw at least five additional relevant contributing resonance structures for the molecule shown below. Show a
ows to denote movement of electrons between the resonance structures. No a
ows – no points.
5 points
Identify the following, for the resonance hy
id:
. Total number of molecular o
itals _______________
c. Number of π -type molecular o
itals _______________
d. Total number of sp2-s molecular o
itals _______________
e. Total number of sp3-s molecular o
itals _______________
f. Total number of π electrons _______________
2. (8 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
Shown below is a pharmaceutical agent used as an eye drop during eye examinations for pupil dilation.
A. Designate the major functional group(s) present. Indicate primary, secondary, tertiary, where applicable.
B. Answer the following, regarding the atoms
onds labeled a to d:
a. Name the o
itals involved in formation of the highlighted bond “a”
. Name the o
itals involved in formation of the highlighted bonds “b”
c. Designate the hy
idization of the highlighted atom “c”
d. Designate the hy
idization of the highlighted atom “d”
3. (8 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
a. 4 points
Designate the following as aromatic/non-aromatic/anti-aromatic
. 4 points
Based on what you have learned in Section 1 of Chem212,
iefly describe which of the following reactions is more likely to occur and why?
4. (6 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
Julio, Stephen, and Annie decide to collected the IR spectra of a product they synthesized (molecular formula C4H10O).
After some optical rotation measurements, Xueqing, Mostafa, and Yong have found that the product(s) is a racemic mixture and optically inactive.
Using the above information and the IR spectrum given, justify if one or more of the following, can be molecule A. Explain why or why not for each (i, ii, iii, iv)?
i. Butan-2-ol
ii. Cyclobutanol
iii. Butan-1-ol
iv. Diethyl ether
IR spectrum of the product
5. (9 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
Angela, Yiwei, and Alex like a challenge! They are looking for ideas for compounds to synthesize in lab.
a. 5 points
Draw a cyclohexane (Line bond only. No need to show solid wedge/dashed or chair) molecule containing only C, H, and any halide (F, Cl, Br, or I) with all the following features:
i. Cyclohexane ring with three substitutions
ii. Three units of unsaturation
iii. 2 chiral centers
. 4 points
From the molecule you drew in (a), pick any one chiral stereoisomers. Show the stereoisomer in solid wedge/dashed bonds. Circle all the chiral centers and assign R/S. Show your work (how priority was assigned based on Cahn-Ingold-Prelog method).
6. (12 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
(a) 4 points
For the molecule 2-chloro-4-ethyl-1-isopropylcyclohexane, draw the two most stable stereoisomers. Draw as line bond conformations with dashed and solid wedge bonds.
(b) 4 points
For the two stereoisomers you have drawn in part a), label each chiral centre as R/S Show your work (how priority was assigned based on Cahn-Ingold-Prelog method). What is the relationship between the two (enantiomers/diasteromers/conformers/same molecule)?
(c) 4 points
Pick one of the stereoisomers from part a), show in chair conformation and perform a chair flip transformation.
7. (8 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
a. For the compound: (4R,5R, Z)-5-chloro-4-methylhex-2-ene, draw the following:
. For the following molecule
8. (9 points) Sharing questions on Chegg/other websites or with others, is a violation of McGill’s Academic Integrity policy.
Are the pairs molecules given below (pair a, b, c) related to each other as constitutional isomers, enantiomers, diastereomers, or identical?
Summer 2021 CHEM 212 Midterm Assignment Page 2 | 8
B
N
O
O
S
- H
+
- H
+
A
B
Choice of reaction and description
Stereoisomer 1Stereoisomer 2
Stereoisomer 1Stereoisomer 2
Relationship
i. Lowest energy Newman conformation
(viewing along C4-C5 bond with C4 in the front)
ii. Enantiomer of the compound in Fischer
projections with C1 on top
OH
i.Newman conformation, as shown,
(viewing along C2-C3 bond with C2 in the front)
ii. A Diastereomer of the compound in Fischer
projection with C1 on top
O
N
O
OH
O
a
c
d
Name all the major functional groups
Designate primary secondary, tertiary, if applicable