Question 1

Concentrated alcohols show a _____absorption in the region of 3200-3600cm-1, due to _____.

Accepted Answer

A)  sharp, hydrogen bonding 
B)  broad, hydrogen bonding 
C)  sharp, polarity 
D)  broad, polarity 
A)  sharp, hydrogen bonding 
B)  broad, hydrogen bonding 
C)  sharp, polarity 
D)  broad, polarity

Question 2

Which of the following compounds will have the highest wavenumber for carbonyl absorption?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  II & III 
A)  I 
B)  II 
C)  III 
D)  II & III

Question 3

Provide the structure of the major fragment that results when the molecular ion of
CH3CH2CH2CH2OH undergoes fragmentation via alpha cleavage.

Accepted Answer

Question 4

Electrospray ionization is used to obtain mass spectra of proteins because:

Accepted Answer

A)  it allows for faster fragmentation of molecular ion 
B)  the molecular ion usually does not undergo fragmentation 
C)  it allows for slow fragmentation of molecular ion 
D)  none of these 
A)  it allows for faster fragmentation of molecular ion 
B)  the molecular ion usually does not undergo fragmentation 
C)  it allows for slow fragmentation of molecular ion 
D)  none of these

Question 5

Which one of the following compounds is consistent with the following IR spectrum?   SDBS: National Institute of Advanced Industrial Science and Technology

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 6

Which of the following compounds will have two absorptions at 1820 cm-1 and 1740cm-1?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 7

Which molecular formula is consistent with the following mass spectrum data? M+ .  at m/z= 108, relative height=61.5%
(M+1)+ .  at m/z= 109, relative height=1.5%
(M+2)+ .  at m/z= 110, relative height=61.3%

Accepted Answer

A)  C2H5Br 
B)  C5H12Cl 
C)  C8H12 
D)  C2H7Br 
E)  none of these 
A)  C2H5Br 
B)  C5H12Cl 
C)  C8H12 
D)  C2H7Br 
E)  none of these

Question 8

Presence of bromine produces M+ .  and (M+2)+ .  peaks of equal intensity on a mass spectrum because:

Accepted Answer

A) . 81Br isotope has higher natural abundance than 79Br isotope 
B) . 79Br and 81Br isotopes have almost equal natural abundance 
C) . 79Br isotope has higher natural abundance than 81Br isotope 
D)  none of these 
A) . 81Br isotope has higher natural abundance than 79Br isotope 
B) . 79Br and 81Br isotopes have almost equal natural abundance 
C) . 79Br isotope has higher natural abundance than 81Br isotope 
D)  none of these

Question 9

Which of the m/z values correspond to the molecular ion peak in the following mass spectrum?

Accepted Answer

A)  45 
B)  44 
C)  29 
D)  15 
E)  none of these 
A)  45 
B)  44 
C)  29 
D)  15 
E)  none of these

Question 10

Calculate the degree of unsaturation for C11H8ClBrO.

Accepted Answer

A)  4 
B)  6 
C)  7 
D)  8 
E)  10 
A)  4 
B)  6 
C)  7 
D)  8 
E)  10

Question 11

Which of the following compounds will have the highest wavenumber for carbonyl absorption?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
A)  I 
B)  II 
C)  III 
D)  IV

Question 12

Which of the following compounds will show two sharp absorption at 3300 cm-1 and at 2150 cm-1?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  none of these 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  none of these

Question 13

Which of the following bonds is IR-inactive?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  I & IV 
E)  I & III 
A)  I 
B)  II 
C)  III 
D)  I & IV 
E)  I & III

Question 14

Which of the following compounds will show a broad absorption around 3300 cm-1 and a sharp absorption at 1650 cm-1?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 15

Mass spectrometry is primarily used to determine:

Accepted Answer

A)  molecular formula of a compound 
B)  molecular weight of a compound 
C)  conjugation in a compound 
D)  A & B 
E)  A & C 
A)  molecular formula of a compound 
B)  molecular weight of a compound 
C)  conjugation in a compound 
D)  A & B 
E)  A & C

Question 16

Which of the following is true about the molecular weight and the M+ . m/z value for the following compound?

Accepted Answer

A)  odd molecular weight, m/z-115 
B)  odd molecular weight, m/z-121 
C)  even molecular weight, m/z-96 
D)  even molecular weight, m/z-132 
E)  none of these 
A)  odd molecular weight, m/z-115 
B)  odd molecular weight, m/z-121 
C)  even molecular weight, m/z-96 
D)  even molecular weight, m/z-132 
E)  none of these

Question 17

For the following reaction, which of the following change(s) in the IR spectrum is consistent with conversion of the reactant to the product?

Accepted Answer

A)  absorption at 2150 cm-1 should disappear 
B)  absorption at 3300 cm-1 and 2150cm-1 should disappear 
C)  absorption at 2250 cm-1 should disappear, a new absorption at 3300 cm-1 should appear 
D)  absorption at 1650 cm-1 should disappear, a new absorption at 3300 cm-1 should appear 
E)  absorption at 3300 cm-1 and 2150cm-1 should disappear, a new absorption at 1720 cm-1 should appear 
A)  absorption at 2150 cm-1 should disappear 
B)  absorption at 3300 cm-1 and 2150cm-1 should disappear 
C)  absorption at 2250 cm-1 should disappear, a new absorption at 3300 cm-1 should appear 
D)  absorption at 1650 cm-1 should disappear, a new absorption at 3300 cm-1 should appear 
E)  absorption at 3300 cm-1 and 2150cm-1 should disappear, a new absorption at 1720 cm-1 should appear

Question 18

Which of the following is not true about electromagnetic radiation?

Accepted Answer

A)  frequency is directly proportional to wavelength 
B)  frequency is directly proportional to energy 
C)  frequency is inversely proportional to wavelength 
D)  wavelength is inversely proportional to energy 
E)  none of these 
A)  frequency is directly proportional to wavelength 
B)  frequency is directly proportional to energy 
C)  frequency is inversely proportional to wavelength 
D)  wavelength is inversely proportional to energy 
E)  none of these

Question 19

Which of the following compounds will have a prominent peak at (M-127)?

Accepted Answer

A)  CH3CH2CH2I 
B)  (CH3CH2)3CCH2Cl 
C)  (CH3)3CCH2CH2Br 
D)  (CH3)2CHCH(CH3)2 
E)  none of these 
A)  CH3CH2CH2I 
B)  (CH3CH2)3CCH2Cl 
C)  (CH3)3CCH2CH2Br 
D)  (CH3)2CHCH(CH3)2 
E)  none of these

Question 20

Propose a possible structure for a compound with molecular formula C7H12O2 that shows absorption at 1720 cm-1 and no absorption in the range of 1500-1700 cm-1 or 2600-2800 cm-1 in its IR spectrum.

Accepted Answer

Exam 15: Infrared Spectroscopy and Mass Spectrometry

Concentrated alcohols show a _____absorption in the region of 3200-3600cm-1, due to _____.

Which of the following compounds will have the highest wavenumber for carbonyl absorption?

Provide the structure of the major fragment that results when the molecular ion of CH3CH2CH2CH2OH undergoes fragmentation via alpha cleavage.

Electrospray ionization is used to obtain mass spectra of proteins because:

Which one of the following compounds is consistent with the following IR spectrum? SDBS: National Institute of Advanced Industrial Science and Technology

Which of the following compounds will have two absorptions at 1820 cm-1 and 1740cm-1?

Which molecular formula is consistent with the following mass spectrum data? M+ . at m/z= 108, relative height=61.5% (M+1)+ . at m/z= 109, relative height=1.5% (M+2)+ . at m/z= 110, relative height=61.3%

Presence of bromine produces M+ . and (M+2)+ . peaks of equal intensity on a mass spectrum because:

Which of the m/z values correspond to the molecular ion peak in the following mass spectrum?

Calculate the degree of unsaturation for C11H8ClBrO.

Which of the following compounds will have the highest wavenumber for carbonyl absorption?

Which of the following compounds will show two sharp absorption at 3300 cm-1 and at 2150 cm-1?

Which of the following bonds is IR-inactive?

Which of the following compounds will show a broad absorption around 3300 cm-1 and a sharp absorption at 1650 cm-1?

Mass spectrometry is primarily used to determine:

Which of the following is true about the molecular weight and the M+ . m/z value for the following compound?

For the following reaction, which of the following change(s) in the IR spectrum is consistent with conversion of the reactant to the product?

Which of the following is not true about electromagnetic radiation?

Which of the following compounds will have a prominent peak at (M-127)?

Propose a possible structure for a compound with molecular formula C7H12O2 that shows absorption at 1720 cm-1 and no absorption in the range of 1500-1700 cm-1 or 2600-2800 cm-1 in its IR spectrum.

A Review of General Chemistry: Electrons, Bonds, and Molecular Properties

Molecular Representations

Acids and Bases

Alkanes and Cycloalkanes

Stereoisomerism

Chemical Reactivity and Mechanisms

Substitution Reactions

Alkenes: Structure and Preparation Via Elimination Reactions

Addition Reactions of Alkenes

Alkynes

Radical Reactions

Synthesis

Alcohols and Phenols

Ethers and Epoxides; Thiols and Sulfides

Nuclear Magnetic Resonance Spectroscopy

Conjugated Pi Systems and Pericyclic Reactions

Aromatic Compounds

Aromatic Substitution Reactions

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Alpha Carbon Chemistry: Enols and Enolates

Amines

Carbohydrates

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

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Concentrated alcohols show a _absorption in the region of 3200-3600cm^-1, due to _.

Provide the structure of the major fragment that results when the molecular ion of CH₃CH₂CH₂CH₂OH undergoes fragmentation via alpha cleavage.

Which of the following compounds will have two absorptions at 1820 cm^-1 and 1740cm^-1?

Which molecular formula is consistent with the following mass spectrum data? M⁺ ^. at m/z= 108, relative height=61.5% (M+1)⁺ ^. at m/z= 109, relative height=1.5% (M+2)⁺ ^. at m/z= 110, relative height=61.3%

Presence of bromine produces M⁺ ^. and (M+2)⁺ ^. peaks of equal intensity on a mass spectrum because:

Calculate the degree of unsaturation for C₁₁H₈ClBrO.

Which of the following compounds will show two sharp absorption at 3300 cm^-1 and at 2150 cm^-1?

Which of the following compounds will show a broad absorption around 3300 cm^-1 and a sharp absorption at 1650 cm^-1?

Which of the following is true about the molecular weight and the M⁺ ^. m/z value for the following compound?

Propose a possible structure for a compound with molecular formula C₇H₁₂O₂ that shows absorption at 1720 cm^-1 and no absorption in the range of 1500-1700 cm^-1 or 2600-2800 cm^-1 in its IR spectrum.