Question 1

Which of the following molecules has a characteristic stretch at 3300 cm-1?

Accepted Answer

A)  (CH3)2CHCH2NHCH3 
B)  (CH3)3CH 
C)  (CH3)2CHCCCH3 
D)  (CH3)2CHCH=CH2 
E)  (CH3)2CHCO2CH3 
A)  (CH3)2CHCH2NHCH3 
B)  (CH3)3CH 
C)  (CH3)2CHCCCH3 
D)  (CH3)2CHCH=CH2 
E)  (CH3)2CHCO2CH3

Question 2

A nonlinear molecule with n atoms generally has ________ fundamental vibrational modes.

Accepted Answer

A)  2n 
B)  2n - 2 
C)  3n 
D)  3n - 3 
E)  3n - 6 
A)  2n 
B)  2n - 2 
C)  3n 
D)  3n - 3 
E)  3n - 6

Question 3

Arrange the following IR bond stretches in order of increasing wavenumber:
C-O, C-C, O-H, and C=C.

Accepted Answer

C­O < C-C

Question 4

The energy of a photon is ________ proportional to its frequency.

Accepted Answer

The answer of The energy of a photon is ________...

Question 5

The IR spectrum of a sample contains absorptions at 3050, 2950, and 1620 cm-1. To what class of organic compound does this sample most likely belong?

Accepted Answer

A)  alkane 
B)  alkene 
C)  alkyne 
D)  ester 
E)  alcohol 
A)  alkane 
B)  alkene 
C)  alkyne 
D)  ester 
E)  alcohol

Question 6

Which of the following molecules would have the highest frequency carbonyl stretch?

Accepted Answer

A)  (CH3CH2)2CO 
B)  CH3CH2CH2CHO 
C)  CH3CH2CO2CH3 
D)  CH3CH2CH2CO2H 
E)  CH3CH2CH2CONH2 
A)  (CH3CH2)2CO 
B)  CH3CH2CH2CHO 
C)  CH3CH2CO2CH3 
D)  CH3CH2CH2CO2H 
E)  CH3CH2CH2CONH2

Question 7

The frequency of the stretching vibration of a bond in IR spectroscopy depends on what two quantities?

Accepted Answer

A)  the stiffness of the bond and the electronegativity of the atoms 
B)  the electronegativity of the atoms and the nuclear charges of the atoms 
C)  the masses of the atoms and the stiffness of the bond 
D)  the nuclear charges of the atoms and the atomic radii 
E)  the electronegativity of the atoms and the masses of the atoms 
A)  the stiffness of the bond and the electronegativity of the atoms 
B)  the electronegativity of the atoms and the nuclear charges of the atoms 
C)  the masses of the atoms and the stiffness of the bond 
D)  the nuclear charges of the atoms and the atomic radii 
E)  the electronegativity of the atoms and the masses of the atoms

Question 8

Which region of the electromagnetic spectrum, IR or UV, contains photons of the higher energy?

Accepted Answer

The answer of Which region of the electromagnetic spectrum, IR...

Question 9

How could IR spectroscopy be used to distinguish between the following pair of compounds?
(CH3)3N and CH3NHCH2CH3

Accepted Answer

N-H absorp

Question 10

In a mass spectrum, the peak of greatest abundance is referred to as the ________.

Accepted Answer

The answer of In a mass spectrum, the peak of...

Question 11

Which of the following structures is consistent with the mass spectrum shown below?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 12

How could IR spectroscopy be used to distinguish between the following pair of compounds?
HOCH2CH2CHO and CH3CH2CO2H

Accepted Answer

A carboxylic acid will have a

Question 13

Which compound would be expected to show intense IR absorption at 3363, 3185, 1660 cm-1?

Accepted Answer

A)  CH3CH2CH2OH 
B)  (CH3)2CHNH2 
C)  CH3CH2CONH2 
D)  but-1-ene 
A)  CH3CH2CH2OH 
B)  (CH3)2CHNH2 
C)  CH3CH2CONH2 
D)  but-1-ene

Question 14

Which of the following most closely matches the C꓿C stretching frequency?

Accepted Answer

A)  3300 
B)  3000 
C)  2200 
D)  1700 
E)  1200 
A)  3300 
B)  3000 
C)  2200 
D)  1700 
E)  1200

Question 15

In a mass spectrum, what m/z value would correspond to the following fragment?

Accepted Answer

The answer of In a mass spectrum, what m/z value...

Question 16

When a compound contains a sulfur atom, its mass spectrum contains a larger than usual ________ peak.

Accepted Answer

A)  M-2 
B)  M-1 
C)  M 
D)  M+1 
E)  M+2 
A)  M-2 
B)  M-1 
C)  M 
D)  M+1 
E)  M+2

Question 17

If the mass spectrum of chlorobenzene shows a peak with an m/z value of 114, having an abundance of 15%, calculate the m/z value and approximate abundance of the molecular ion peak.

Accepted Answer

m/z = 112,

Question 18

When a high energy electron impacts molecule M in the ionization chamber, what type of species is initially produced?

Accepted Answer

A)  cation 
B)  anion 
C)  radical 
D)  radical cation 
E)  radical anion 
A)  cation 
B)  anion 
C)  radical 
D)  radical cation 
E)  radical anion

Question 19

Which compound would be expected to show intense IR absorption at 1640 cm-1?

Accepted Answer

A)  hex-1-ene 
B)  2-methylheptane 
C)  CH3CH2CH2OH 
D)  CH3CH2COCH3 
A)  hex-1-ene 
B)  2-methylheptane 
C)  CH3CH2CH2OH 
D)  CH3CH2COCH3

Question 20

Absorption of what type of electromagnetic radiation results in transitions among allowed vibrational motions?

Accepted Answer

A)  X-rays 
B)  radio waves 
C)  microwaves 
D)  ultraviolet light 
E)  infrared light 
A)  X-rays 
B)  radio waves 
C)  microwaves 
D)  ultraviolet light 
E)  infrared light

Exam 12: Infrared Spectroscopy and Mass Spectrometry

Which of the following molecules has a characteristic stretch at 3300 cm-1?

A nonlinear molecule with n atoms generally has ________ fundamental vibrational modes.

Arrange the following IR bond stretches in order of increasing wavenumber: C-O, C-C, O-H, and C=C.

The energy of a photon is ________ proportional to its frequency.

The IR spectrum of a sample contains absorptions at 3050, 2950, and 1620 cm-1. To what class of organic compound does this sample most likely belong?

Which of the following molecules would have the highest frequency carbonyl stretch?

The frequency of the stretching vibration of a bond in IR spectroscopy depends on what two quantities?

Which region of the electromagnetic spectrum, IR or UV, contains photons of the higher energy?

How could IR spectroscopy be used to distinguish between the following pair of compounds? (CH3)3N and CH3NHCH2CH3

In a mass spectrum, the peak of greatest abundance is referred to as the ________.

Which of the following structures is consistent with the mass spectrum shown below?

How could IR spectroscopy be used to distinguish between the following pair of compounds? HOCH2CH2CHO and CH3CH2CO2H

Which compound would be expected to show intense IR absorption at 3363, 3185, 1660 cm-1?

Which of the following most closely matches the C꓿C stretching frequency?

In a mass spectrum, what m/z value would correspond to the following fragment?

When a compound contains a sulfur atom, its mass spectrum contains a larger than usual ________ peak.

If the mass spectrum of chlorobenzene shows a peak with an m/z value of 114, having an abundance of 15%, calculate the m/z value and approximate abundance of the molecular ion peak.

When a high energy electron impacts molecule M in the ionization chamber, what type of species is initially produced?

Which compound would be expected to show intense IR absorption at 1640 cm-1?

Absorption of what type of electromagnetic radiation results in transitions among allowed vibrational motions?

Introduction and Review

Structure and Properties of Organic Molecules

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides: Nucleophilic Substitution and Elimination

Structure and Synthesis of Alkenes

Reactions of Alkenes

Alkynes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

Which of the following molecules has a characteristic stretch at 3300 cm^-1?

The IR spectrum of a sample contains absorptions at 3050, 2950, and 1620 cm^-1. To what class of organic compound does this sample most likely belong?

How could IR spectroscopy be used to distinguish between the following pair of compounds? (CH₃)₃N and CH₃NHCH₂CH₃

How could IR spectroscopy be used to distinguish between the following pair of compounds? HOCH₂CH₂CHO and CH₃CH₂CO₂H

Which compound would be expected to show intense IR absorption at 3363, 3185, 1660 cm^-1?

Which compound would be expected to show intense IR absorption at 1640 cm^-1?