Question 1

The mass spectrum of which compound has M+ and M+2 peaks of approximately equal intensity?

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

Question 2

Arrange the following regions of the electromagnetic spectrum in order of increasing energy: microwave, UV, visible, and IR.

Accepted Answer

microwave

Question 3

How could IR spectroscopy be used to distinguish between the following pair of compounds?
CH3CH2C   
CH and CH3C   
CCH3

Accepted Answer

Terminal alkyne stre

Question 4

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 5

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

Accepted Answer

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

Question 6

Absorption ________ is the measurement of the amount of light absorbed by a compound as a function of the wavelength of light.

Accepted Answer

The answer of Absorption ________ is the measurement of the...

Question 7

Sodium borohydride can be used to reduce cyclohexanone to cyclohexanol. How could one use IR to determine if all starting material had been consumed?

Accepted Answer

Presence of C @#IMG-DLM& O str

Question 8

Consider 3-pentanone (shown below). What m/z fragments would you expect to see in the mass spectrum of this compound?

Accepted Answer

A)  15 
B)  43 
C)  57 
D)  You would expect to see all three fragments. 
A)  15 
B)  43 
C)  57 
D)  You would expect to see all three fragments.

Question 9

Relative abundance is the unit along the y-axis in a mass spectrum. What are the units on the x-axis?

Accepted Answer

A)  mass/charge (m/z) 
B)  mass (m) 
C)  molecular weight (amu) 
D)  frequency (ν) 
A)  mass/charge (m/z) 
B)  mass (m) 
C)  molecular weight (amu) 
D)  frequency (ν)

Question 10

What IR absorption is characteristic of the C=O stretch in aldehydes?

Accepted Answer

A)  3500 cm-1 
B)  3300 cm-1 
C)  2950 cm-1 
D)  2250 cm-1 
E)  1710 cm-1 
A)  3500 cm-1 
B)  3300 cm-1 
C)  2950 cm-1 
D)  2250 cm-1 
E)  1710 cm-1

Question 11

What wavenumber corresponds to the wavelength of 4 μm?

Accepted Answer

The answer of What wavenumber corresponds to the wavelength of...

Question 12

What wavelength in mm is equivalent to a wavenumber of 1750 cm-1?

Accepted Answer

Question 13

Which of the following structures is consistent with the IR spectra shown below?

Accepted Answer

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

Question 14

Which bond in the structure below would give rise to the highest absorption frequency in an IR spectrum?

Accepted Answer

A)  C sp2-H 
B)  C sp3-H 
C)  C-D 
D)  C=C 
A)  C sp2-H 
B)  C sp3-H 
C)  C-D 
D)  C=C

Question 15

The mass spectrum of alcohols often fail to exhibit detectable M+ peaks but instead show relatively large ________ peaks.

Accepted Answer

A)  M+1 
B)  M+2 
C)  M-16 
D)  M-17 
E)  M-18 
A)  M+1 
B)  M+2 
C)  M-16 
D)  M-17 
E)  M-18

Question 16

Which compound would be expected to show intense IR absorption at 2820, 2710 and

Accepted Answer

A)  CH3COCH2CH3 
B)  PhCOCH3 
C)  PhCHO 
D)  CH2
   
CHCOCH3 
A)  CH3COCH2CH3 
B)  PhCOCH3 
C)  PhCHO 
D)  CH2
   
CHCOCH3

Question 17

What are the predicted m/z values (masses) and relative heights of all the molecular ions of 1-bromoethane that would appear on a mass spectrum (excluding peaks produced by 13C and 2H)?

Accepted Answer

A)  M+ peak at m/z=108 and an M+1 peak at m/z =110
The M+1 peak is approximately 1/2 the height of the M+ peak. 
B)  M+ peak at m/z= 79 and an M+1 peak at at m/z = 81
The M+1 peak is approximately the same height as the M+ peak. 
C)  M+ peak at m/z = 108 and an M+2 peak at m/z = 110
The M+2 peak is approximately the same height as the M+ peak. 
D)  M+ peak at m/z = 108 and an M+2 peak at m/z = 110
M+2 peak is approximately 1/2 the height of the M+ peak. 
E)  M+ peak at m/z = 79 and an M+1 peak at m/z = 81
The M+1 peak is approximately 1/2 the height of the M+ peak. 
A)  M+ peak at m/z=108 and an M+1 peak at m/z =110
The M+1 peak is approximately 1/2 the height of the M+ peak. 
B)  M+ peak at m/z= 79 and an M+1 peak at at m/z = 81
The M+1 peak is approximately the same height as the M+ peak. 
C)  M+ peak at m/z = 108 and an M+2 peak at m/z = 110
The M+2 peak is approximately the same height as the M+ peak. 
D)  M+ peak at m/z = 108 and an M+2 peak at m/z = 110
M+2 peak is approximately 1/2 the height of the M+ peak. 
E)  M+ peak at m/z = 79 and an M+1 peak at m/z = 81
The M+1 peak is approximately 1/2 the height of the M+ peak.

Question 18

The two most abundant isotopes of boron are 10B and 11B, with 11B being about 4 times more abundant. In the mass spectrum of trimethylborate [(CH3O)3B], ________.

Accepted Answer

A)  the peaks at m/z 103 and m/z 104 have equivalent intensities 
B)  the peak at m/z 103 has an intensity which is 4 times that of the m/z 104 peak 
C)  the peak at m/z 103 has an intensity which is 1/4 the intensity of the peak at m/z 104 
D)  none of the above 
A)  the peaks at m/z 103 and m/z 104 have equivalent intensities 
B)  the peak at m/z 103 has an intensity which is 4 times that of the m/z 104 peak 
C)  the peak at m/z 103 has an intensity which is 1/4 the intensity of the peak at m/z 104 
D)  none of the above

Question 19

Which compound lacks a strong, characteristic IR absorption near 1700 cm-1?

Accepted Answer

A)  CH3CH2CO2H 
B)  CH3CH2CHO 
C)  (CH3CH2)2C=O 
D)  (CH3CH2)2O 
E)  H3CH2CO2CH3 
A)  CH3CH2CO2H 
B)  CH3CH2CHO 
C)  (CH3CH2)2C=O 
D)  (CH3CH2)2O 
E)  H3CH2CO2CH3

Question 20

In IR spectroscopy, the C-O bond has a ________ frequency than the C-N bond because ________.

Accepted Answer

A)  higher; an O atom has more mass than an N atom 
B)  lower; an O atom has more mass than an N atom 
C)  higher; an O atom has more electronegativity than an N atom 
D)  lower; an O atom has more electronegativity than an N atom 
E)  higher; an O atom has an even number of neutrons 
A)  higher; an O atom has more mass than an N atom 
B)  lower; an O atom has more mass than an N atom 
C)  higher; an O atom has more electronegativity than an N atom 
D)  lower; an O atom has more electronegativity than an N atom 
E)  higher; an O atom has an even number of neutrons

Exam 12: Infrared Spectroscopy and Mass Spectrometry

The mass spectrum of which compound has M+ and M+2 peaks of approximately equal intensity?

Arrange the following regions of the electromagnetic spectrum in order of increasing energy: microwave, UV, visible, and IR.

How could IR spectroscopy be used to distinguish between the following pair of compounds? CH3CH2C CH and CH3C CCH3

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

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

Absorption ________ is the measurement of the amount of light absorbed by a compound as a function of the wavelength of light.

Sodium borohydride can be used to reduce cyclohexanone to cyclohexanol. How could one use IR to determine if all starting material had been consumed?

Consider 3-pentanone (shown below). What m/z fragments would you expect to see in the mass spectrum of this compound?

Relative abundance is the unit along the y-axis in a mass spectrum. What are the units on the x-axis?

What IR absorption is characteristic of the C=O stretch in aldehydes?

What wavenumber corresponds to the wavelength of 4 μm?

What wavelength in mm is equivalent to a wavenumber of 1750 cm-1?

Which of the following structures is consistent with the IR spectra shown below?

Which bond in the structure below would give rise to the highest absorption frequency in an IR spectrum?

The mass spectrum of alcohols often fail to exhibit detectable M+ peaks but instead show relatively large ________ peaks.

Which compound would be expected to show intense IR absorption at 2820, 2710 and

What are the predicted m/z values (masses) and relative heights of all the molecular ions of 1-bromoethane that would appear on a mass spectrum (excluding peaks produced by 13C and 2H)?

The two most abundant isotopes of boron are 10B and 11B, with 11B being about 4 times more abundant. In the mass spectrum of trimethylborate [(CH3O)3B], ________.

Which compound lacks a strong, characteristic IR absorption near 1700 cm-1?

In IR spectroscopy, the C-O bond has a ________ frequency than the C-N bond because ________.

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 M⁺ and M+2 peaks of approximately equal intensity?

How could IR spectroscopy be used to distinguish between the following pair of compounds? CH₃CH₂C CH and CH₃C CCH₃

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

What wavelength in mm is equivalent to a wavenumber of 1750 cm^-1?

The mass spectrum of alcohols often fail to exhibit detectable M⁺ peaks but instead show relatively large ________ peaks.

What are the predicted m/z values (masses) and relative heights of all the molecular ions of 1-bromoethane that would appear on a mass spectrum (excluding peaks produced by ¹³C and²H)?

The two most abundant isotopes of boron are ¹⁰B and ¹¹B, with ¹¹B being about 4 times more abundant. In the mass spectrum of trimethylborate [(CH₃O)₃B], ________.

Which compound lacks a strong, characteristic IR absorption near 1700 cm^-1?

In IR spectroscopy, the C-O bond has a frequency than the C-N bond because .