Question 1

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 E

Question 2

Which sequence correctly ranks the regions of the electromagnetic spectrum in order of increasing energy?
1) infrared 2) ultraviolet 3) radio wave

Accepted Answer

A)  3 < 1 < 2 
B)  3 < 2 < 1 
C)  2 < 1 < 3 
D)  1 < 3 < 2 
A)  3 < 1 < 2 
B)  3 < 2 < 1 
C)  2 < 1 < 3 
D)  1 < 3 < 2 A

Question 3

The mass spectrum of which compound has an M+2 peak that has intensity that is about 25% of its M+ peak?

Accepted Answer

A)  3-bromopentane 
B)  3-pentanol 
C)  pentane 
D)  3-chloropentane 
E)  3-iodopentane 
A)  3-bromopentane 
B)  3-pentanol 
C)  pentane 
D)  3-chloropentane 
E)  3-iodopentane D

Question 4

Absorption of what type of electromagnetic radiation results in ionization?

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

Question 5

Which of the following stretches tends to be the least intense?

Accepted Answer

A)  O-H (alcohol) 
B)  O-H (carboxylic acid) 
C)  C-H 
D)  C=O 
E)  C=C 
A)  O-H (alcohol) 
B)  O-H (carboxylic acid) 
C)  C-H 
D)  C=O 
E)  C=C

Question 6

What m/z characterizes a strong peak in the mass spectrum of cyclopentanol?

Accepted Answer

A)  86 
B)  85 
C)  84 
D)  70 
E)  68 
A)  86 
B)  85 
C)  84 
D)  70 
E)  68

Question 7

An infrared wavelength of 5.81μm is equivalent to a wavenumber of ________ cm-1.

Accepted Answer

Question 8

Which of the following factors influences the intensity of a peak in the IR spectrum of a molecule?

Accepted Answer

A)  mass of atoms 
B)  dipole moment 
C)  bond strength 
D)  bond length 
A)  mass of atoms 
B)  dipole moment 
C)  bond strength 
D)  bond length

Question 9

Which statement best explains why a carbonyl absorbs infrared radiation at a higher frequency than an alkene absorption?

Accepted Answer

A)  Oxygen has a higher molecular mass than carbon. 
B)  A carbonyl bond is more polarized than an alkene bond. 
C)  Resonance delocalization of electrons invokes greater single bond character in a carbonyl bond. 
D)  A carbonyl π bond is much stronger than an alkene π bond. 
A)  Oxygen has a higher molecular mass than carbon. 
B)  A carbonyl bond is more polarized than an alkene bond. 
C)  Resonance delocalization of electrons invokes greater single bond character in a carbonyl bond. 
D)  A carbonyl π bond is much stronger than an alkene π bond.

Question 10

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

Accepted Answer

A)  3300 cm-1 
B)  2950 cm-1 
C)  2200 cm-1 
D)  1600 cm-1 
E)  1200 cm-1 
A)  3300 cm-1 
B)  2950 cm-1 
C)  2200 cm-1 
D)  1600 cm-1 
E)  1200 cm-1

Question 11

The presence of which element is indicated by a peak at m/z 127 and a characteristic 127-unit gap in the mass spectrum?

Accepted Answer

A)  Br 
B)  Cl 
C)  I 
D)  N 
E)  S 
A)  Br 
B)  Cl 
C)  I 
D)  N 
E)  S

Question 12

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

Accepted Answer

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

Question 13

What two functional groups are represented in the following IR spectrum?

Accepted Answer

aromatic r

Question 14

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 15

Which of the following has a C-H stretch that occurs at the lowest stretching frequency?

Accepted Answer

A)  hexane 
B)  hex-1-ene 
C)  (
E) -hex-2-ene 
D)  hex-1-yne 
E)  hex-2-yne 
A)  hexane 
B)  hex-1-ene 
C)  (
E) -hex-2-ene 
D)  hex-1-yne 
E)  hex-2-yne

Question 16

Rank the following bonds in order of increasing stretching frequency (cm-1) in IR spectroscopy:

Accepted Answer

C-O < C=O

Question 17

Using IR, how could you tell if the reaction below was complete?

Accepted Answer

The broad peak at 3400 cm^-1 woul

Question 18

Which of the following bonds, C-N, C   
N, or C   
N, has an IR stretch around 1600 cm-1?

Accepted Answer

Question 19

What IR absorption is characteristic of the terminal C-H stretch in terminal alkynes?

Accepted Answer

A)  3500 cm-1 
B)  3300 cm-1 
C)  2400 cm-1 
D)  2250 cm-1 
E)  1710 cm-1 
A)  3500 cm-1 
B)  3300 cm-1 
C)  2400 cm-1 
D)  2250 cm-1 
E)  1710 cm-1

Question 20

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

Accepted Answer

N-H absorption near

Exam 12: Infrared Spectroscopy and Mass Spectrometry

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

Which sequence correctly ranks the regions of the electromagnetic spectrum in order of increasing energy? 1) infrared 2) ultraviolet 3) radio wave

The mass spectrum of which compound has an M+2 peak that has intensity that is about 25% of its M+ peak?

Absorption of what type of electromagnetic radiation results in ionization?

Which of the following stretches tends to be the least intense?

What m/z characterizes a strong peak in the mass spectrum of cyclopentanol?

An infrared wavelength of 5.81μm is equivalent to a wavenumber of ________ cm-1.

Which of the following factors influences the intensity of a peak in the IR spectrum of a molecule?

Which statement best explains why a carbonyl absorbs infrared radiation at a higher frequency than an alkene absorption?

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

The presence of which element is indicated by a peak at m/z 127 and a characteristic 127-unit gap in the mass spectrum?

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

What two functional groups are represented in the following IR spectrum?

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

Which of the following has a C-H stretch that occurs at the lowest stretching frequency?

Rank the following bonds in order of increasing stretching frequency (cm-1) in IR spectroscopy:

Using IR, how could you tell if the reaction below was complete?

Which of the following bonds, C-N, C N, or C N, has an IR stretch around 1600 cm-1?

What IR absorption is characteristic of the terminal C-H stretch in terminal alkynes?

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

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides; Nucleophilic Substitution

Structure and Synthesis of Alkenes; Elimination

Reactions of Alkenes

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

The mass spectrum of which compound has an M+2 peak that has intensity that is about 25% of its M⁺ peak?

An infrared wavelength of 5.81μm is equivalent to a wavenumber of ________ cm^-1.

Rank the following bonds in order of increasing stretching frequency (cm^-1) in IR spectroscopy:

Which of the following bonds, C-N, C N, or C N, has an IR stretch around 1600 cm^-1?

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