CHEM 204 Midterm 1 Practice
These questions have been taken from a previous CHEM 204 midterm examination. The question
style and level of difficulty are typical of what you can expect on the upcoming midterm
At the time of this posting, not all of the topi cs being tested have been pres ented in class. There
are thus some questions that you will not be able to do until closer to the midterm date.
You are encouraged to work on these questions in your study groups and to discuss the answers
and problem-solving strategies via the course WebCT Bulletin Board. Use the question numbers as
thread subjects in order to keep the discussion organized.
Please do not ask your instructor to check y our answers to these questions. You have ready
access to your lecture notes and your textbook and thus you should be able to do all of these
questions and have confidence in your final answe rs. The answers to these questions will be
posted a couple of days before the exam. It is in your best interest to work through these problems
long before the answers are posted! 1. (28 marks)
a) Circle the compound with thesmallestapK value.
O OH NH NH Cl
b) Circle the most acidic hydrogen(s)in each of the molecules shown below.
H 3 O H H H H
H CH 3 H C OH
H H H C H HO
H H H O
c) Circle themajorproduct of the following L4AlH reduction.
O CH2OH CH2NH 2 CH 3 CH2NH2
2) H workup
O CH OH CH OH CH OH
2 2 2 CH3
d) Circle the side of the equilibrium that isfavouredin the following two situations.
i) CH 3H C2 OH2+ CH 3H C2 O2+
ii) CH 3H 2 + CH C3 N2 2 + Na Cl CH 3H C3 + CH CH N3 Na2
- 2 of 12 - 1. … continued (28 marks)
e) Fill in the boxes to indicate themost/least acidiccompound from the following.
OH OH OH OH
3 H CO 2
A B C D
Most Acidic Least Acidic
f) Circle themost appropriateterm to describe the type of polymer shown.
polyamine polyether polygamist polyester polyamide
H O H O H O
N N N N N N
H O H O H O
g) Draw thebest monomer(s)that could be used to prepare the polymer in part f) above?
h) The anion shown below has severaladditional resonance structuresthat delocalize the negative
charge onto other atomic centres than the phenolic oxygen. Clearly indicate, using asterisks (*), on
the “skeletal structure” the sites of this electron density — the phenolic oxygen has already been
done for you.
Hint: Draw the resonance structures involving the phenolic oxygen before completing the diagram.
O O *
- 3 of 12 - 2. (9 marks)
a) Shown below is the Fischer projection representation of L-talose.
C H C H
H OH O
i) Complete the Fischer projection to the right of the given formula to show D-talose.
ii) Complete the chair conformational diagram to showβ-D-talopyranose.
b) Check the appropriate box below each structure to indicate whether each of the compounds would
yield anoptically activeproduct upon reaction with nitric acid.
O O O O
C H C H C H C H
H OH H OH H OH H OH
H OH H OH HO H HO H
H OH HO H HO H H OH
H OH HO H H OH HO H
CH2OH CH 2H CH2OH CH2OH
Yes ❐ Yes ❐ Yes ❐ Yes ❐
No ❐ No ❐ No ❐ No ❐
- 4 of 12 - 3. (9 marks)
a) Answer the questions below regarding the disaccharide shown.
HOH 2 O
HO H OH
OH HO OH
A O O CH OH
i) ComponentB is an ❐ Aldose ❐ Ketose ❐ Neither
ii) The disaccharide is a reducing sugar ❐ Yes ❐ No ❐ Impossible to know
iii) The disaccharide can mutarotate ❐ Yes ❐ No ❐ Impossible to know
iv) ComponentA is a