Exam 2 Topics and Study
Tips/Strategies
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Hannah J.
Chem 331
Dr. Winter
10/4/15
Exam 2 Topics:
The following is a (checkable) list of the topics you should know and understand for exam 2:
Ch. 5:
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What a plane of symmetry is and how to find it/them in a molecule
Which molecular geometries do and don’t superimpose on their mirror images
Definition and identification (i.e. from R/S notation) of enantiomers. Given a molecule, you
should be able to draw an enantiomer. Also, know which physical property differs between
enantiomers (and that it is the only one that is different).
Definition and identification of a chiral center.
Know R & S naming:
o Purpose/for which kinds of molecules it is used
o How to assign R/S naming either by rotating the molecule on paper or using the thumb
rule (pick whichever you can use efficiently and correctly)
o Be able to name whole molecules, including R & S notation
Definition of a racemic mixture or racemate
Definition and identification (i.e. from R/S notation) of diastereomers. Given a molecule, you
should be able to draw a diastereomer. Know that only molecules with multiple chiral centers can
be diastereomers. Also, know which physical property/properties differ between diastereomers.
Definition of a meso compound
Know the formula for the maximum number of stereoisomers in a molecule and be able to
determine the actual number of unique stereoisomers present in a molecule based on symmetry.
Ch. 12:
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Mass Spectrometry
o Have a simple conceptual understanding of how mass spectrometry works and what we
use it to find (the exact (to about 4 decimal places) molecular weight of the molecule,
which enables us the find the formula). Also know what and where on the spectrum the
M+, or molecular ion, peak is and what we use it for (see above parentheses).
o Know why we consider the radicals that a mass spectrometer registers to have the same
molecular weight as their uncharged counterparts.
o Be able to explain why there is a small peak 1 g/mol greater than the M+ peak (based on
13
C isotopes).
Infrared (IR) Spectrometry
o Have a simple conceptual understanding of how infrared (IR) spectrometry works and
what we use it to find (functional groups).
o Know what and where the fingerprint region is and that we always ignore it.
o Know the peak shapes associated with a carbonyl, alcohol, and amine (primary,
secondary, etc.). Especially know that alcohol is a big, broad peak around 3500 cm-1.
o Be comfortable using an IR chart (like the one on page 439 in the textbook) to identify
functional groups from an IR spectrum or written peak locations.
Be able to distinguish Mass, IR, and NMR spectra when you’re not told which is which
Ch. 13:
1060 Hixson-Lied Student Success Center  515-294-6624  sistaff@iastate.edu  http://www.si.iastate.edu
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Have a simple conceptual understanding of how Nuclear Magnetic Resonance (NMR)
spectrometry works and what we use it to find (the structure of a molecule)
Understand the difference between 1H and 13C NMR and know that we primarily use 1H (know
why)
Know which end is downfield and upfield, high and low chemical shifts, high and low frequency,
more and less shielded and why a peak registers more or less downfield based on the
electronegativity of the atom it’s connected to
Understand that we measure NMR spectra relative to a standard (TMS) to even out results for
more and less expensive NMR spectrometers (better and worse magnets used) and that that’s why
frequency is given in ppm (parts per million).
Be able to identify how many peaks a given molecule will have in either an 1H or 13C NMR
spectrum based on total number of H’s/C’s and symmetry. Also, know what it means for pieces
of a molecule to be chemically equivalent and how to determine chemical equivalency
Understand and be able to determine relative integration for the different peaks of a molecule
Coupling: what it is, which H’s do and do not couple with each other, and be able to determine
the number of peaks/coupling pattern (singlet, doublet, etc.) for any H in the molecule using the n
+ 1 rule. Also, know that OH and NH do not couple (they are always singlets) and are not
included in coupling counts for neighboring H’s
Understand the distinction between relative integration and coupling (so you don’t get them
confused).
Be comfortable using an NMR chart (like the one on page 475 in the textbook) to identify what
each peak from an NMR spectrum or written peak locations represents, including the aromatic
ring (Ar or Aryl) and halide (Hal = F, Cl, Br, I) abbreviations.
Be comfortable determining structure from either the NMR, IR spectra or just the written peak
locations (with the δ notation—also understand how relative integration (e.g. 2H, 6H, etc.) and
coupling (e.g. s, d, etc.) are given in the written version)
Know how to determine degrees of unsaturation (DOU) and what the number means. Know also
that a DOU of 4 or greater almost always means that there is an aromatic ring in the molecule.
KEY: Be Able to Determine Structures from 1H NMR (possibly also given IR) Spectra. Use the
“detective/clue” 5-step method given in class or another that works reliably. Do plenty of practice
problems on this!
Study Tips/Strategies:
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Go through your notes, reading them and highlighting important topics and details (This is a good
first step in studying for any exam. If you don’t have good notes, ask a friend.)
Redo in-class examples and/or SI worksheets without looking at the solutions, then check your
work
Do end-of-chapter problems (Ch. 5, 12, 13) in textbook and/or google simple IR/NMR problems
Read end-of-chapter summaries and passages on confusing topics in textbook
Form a study group and study together
Make flashcards for the memorized items and go through them until you can identify the opposite
side both ways in any order on the first try
Finish all applicable Sapling homework & look back through past assignments
Come to SI 
DO THE PRACTICE EXAM POSTED ON BLACKBOARD (if it’s helpful to you, consider
taking it once without studying to gauge where you are, then retake it after studying)
Make a list of reminders about things you might forget (e.g. Label formal charges, calculate
D.O.U. first on NMR problems)
Ask a friend, me (your SI leader), or Dr. Winter in person or via email about any topics that you
are still confused on after studying
Power through and don’t forget to breathe! If you’ve been putting in the effort and gotten a good
grasp on the material, you’ll be successful on the exam—you can do it! 