Chem 241 Fall 2025
Exam 12/9/25 6:30-8:20
Name_______________________________UW email:
(PRINT IN ALL CAPITALS)
You have 110 minutes for this exam. It contains this cover sheet, a data page, and 12 pages of
questions. You are allowed a molecular model kit, but no additional resources (no phones,
calculators, etc.) You can answer the questions in any order. Please initial each page.
My personal advice is to skim through the exam initially and pick out questions you feel
confident about, then work around to the remaining questions. Each question indicates how
many points it is worth. If an explanation question gives a sentence limit, please keep to
that.
Question 1 2 3 4 5 6 7 8 9 10 11 12 Total
Points 15 14 13 15 12 10 13 13 13 10 12 20 160
, List of common IR frequencies NMR chemical shifts
IR Functional Bond (stretch Characteristic NMR Type of proton Structure , ppm
Group unless noted) Absorption Cyclopropane C3H6 0.2
(cm-1) Primary alkane R-CH3 0.8-1.2
Alkane C-H 2950-2850 Secondary alkane R2-CH2 1.2-1.4
C-H 3100-3010 Tertiary alkane R3C-H 1.4-1.7
Alkene
C=C 1680-1620 Vinylic C=C-H 4.6-5.9
C-H ~3300 Acetylenic C≡C-H 2-3
Alkyne
C≡C 2260-2100 Aromatic Ar-H 6.5-8
C-H ~3030 Benzylic Ar-C-H 2.2-3
Benzene C-H bend 860-680 Allylic C=C-C-H 1.7-2.7
C=C 1640-1500 Halides H-C-X 2.5-4
O-H 3550-3200 H-C-OH 3.4-4
Alcohol/Phenol Alcohols
(broad, s) R-C-O-H 1-5.5 (b, v)
O-H 3400-2500 Phenols Ar-O-H 4-12 (b, v)
Carboxylic acid (broad, v) Ethers H-C-OR 3.3-4
C=O 1780-1710 (s) Thiols, sulfides, H-C-SR 3-3.5
Amine N-H 3500-3300 amines H-C-NR2
Nitrile C≡N 2260-2220 R-NH2, R-SH 1-5 (b, v)
C-H ~2720 RC(O)O-C-H 3.7-4.1
Aldehyde Esters
C=O 1740-1690 (s) H-C-C(O)O-R 2-2.2
Ketone C=O 1750-1680 (s) H-C-C(O)-OH 2-2.6
Ester C=O 1750-1735 (s) Carboxylic Acids
R-C(O)O-H 10-12 (b,v)
N-H 3700-3500 -Carbonyls H-C-C=O 2-2.7
Amide
C=O 1690-1630 (s) Aldehydic R-C(O)-H 9-10
N-O, N=O ~1530 and Amides R-C(O)-NH-R 5-9 (b, v)
Nitro
~1350 (s) (b=broad peak, v=variable position)
Carbon dioxide C=O 2350
(s=strong peak, v=variable intensity)
NMR Impurities CDCl3 D2O DMSO-d6 Acetone-d6
Residual solvent peak 7.2 (s) 4.8 (s) 2.5 (p) 2.1 (p)
Water 1.6 (s) 4.8 (s) 3.3 (s) 2.8 (might be s or t)
Acetone 2.2 (s) 2.2 (s) 2.1 (s) 2.1 (s)
Diethyl ether 1.2 (t), 3.5 (q) 1.2 (t), 3.6 (q) 1.1 (t), 3.4 (q) 1.1 (t), 3.4 (q)
Methylene chloride 5.3 (s) Not soluble 5.8 (s) 5.6 (s)
NOTE – for the entire exam, explanation questions can be answered in approximately 15-20 words.
If a question says “state”, you don’t have to explain, or even write full sentences. If you write too
much, your full answer may not be read.
Exam 12/9/25 6:30-8:20
Name_______________________________UW email:
(PRINT IN ALL CAPITALS)
You have 110 minutes for this exam. It contains this cover sheet, a data page, and 12 pages of
questions. You are allowed a molecular model kit, but no additional resources (no phones,
calculators, etc.) You can answer the questions in any order. Please initial each page.
My personal advice is to skim through the exam initially and pick out questions you feel
confident about, then work around to the remaining questions. Each question indicates how
many points it is worth. If an explanation question gives a sentence limit, please keep to
that.
Question 1 2 3 4 5 6 7 8 9 10 11 12 Total
Points 15 14 13 15 12 10 13 13 13 10 12 20 160
, List of common IR frequencies NMR chemical shifts
IR Functional Bond (stretch Characteristic NMR Type of proton Structure , ppm
Group unless noted) Absorption Cyclopropane C3H6 0.2
(cm-1) Primary alkane R-CH3 0.8-1.2
Alkane C-H 2950-2850 Secondary alkane R2-CH2 1.2-1.4
C-H 3100-3010 Tertiary alkane R3C-H 1.4-1.7
Alkene
C=C 1680-1620 Vinylic C=C-H 4.6-5.9
C-H ~3300 Acetylenic C≡C-H 2-3
Alkyne
C≡C 2260-2100 Aromatic Ar-H 6.5-8
C-H ~3030 Benzylic Ar-C-H 2.2-3
Benzene C-H bend 860-680 Allylic C=C-C-H 1.7-2.7
C=C 1640-1500 Halides H-C-X 2.5-4
O-H 3550-3200 H-C-OH 3.4-4
Alcohol/Phenol Alcohols
(broad, s) R-C-O-H 1-5.5 (b, v)
O-H 3400-2500 Phenols Ar-O-H 4-12 (b, v)
Carboxylic acid (broad, v) Ethers H-C-OR 3.3-4
C=O 1780-1710 (s) Thiols, sulfides, H-C-SR 3-3.5
Amine N-H 3500-3300 amines H-C-NR2
Nitrile C≡N 2260-2220 R-NH2, R-SH 1-5 (b, v)
C-H ~2720 RC(O)O-C-H 3.7-4.1
Aldehyde Esters
C=O 1740-1690 (s) H-C-C(O)O-R 2-2.2
Ketone C=O 1750-1680 (s) H-C-C(O)-OH 2-2.6
Ester C=O 1750-1735 (s) Carboxylic Acids
R-C(O)O-H 10-12 (b,v)
N-H 3700-3500 -Carbonyls H-C-C=O 2-2.7
Amide
C=O 1690-1630 (s) Aldehydic R-C(O)-H 9-10
N-O, N=O ~1530 and Amides R-C(O)-NH-R 5-9 (b, v)
Nitro
~1350 (s) (b=broad peak, v=variable position)
Carbon dioxide C=O 2350
(s=strong peak, v=variable intensity)
NMR Impurities CDCl3 D2O DMSO-d6 Acetone-d6
Residual solvent peak 7.2 (s) 4.8 (s) 2.5 (p) 2.1 (p)
Water 1.6 (s) 4.8 (s) 3.3 (s) 2.8 (might be s or t)
Acetone 2.2 (s) 2.2 (s) 2.1 (s) 2.1 (s)
Diethyl ether 1.2 (t), 3.5 (q) 1.2 (t), 3.6 (q) 1.1 (t), 3.4 (q) 1.1 (t), 3.4 (q)
Methylene chloride 5.3 (s) Not soluble 5.8 (s) 5.6 (s)
NOTE – for the entire exam, explanation questions can be answered in approximately 15-20 words.
If a question says “state”, you don’t have to explain, or even write full sentences. If you write too
much, your full answer may not be read.
