Question 1

Which molecular formula is consistent with the following mass spectral 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

Question 2

Which of the following is always true about the base peak in a mass spectrum?

Accepted Answer

A)   the peak corresponding to molecular ion
B)   the peak corresponding to the most abundant ion
C)   the peak corresponding to lowest m/z
D)   the peak corresponding to the cation
E)   the peak corresponding to the lowest fragment

Question 3

In mass spectrometry using the electron impact ionization technique, a beam of high-energy electrons initially ejects one electron from the compound being studied. This produces a positively charged ion called the ____________________.

Accepted Answer

The answer of In mass spectrometry using the electron impact...

Question 4

Which of the following electromagnetic radiation has the highest frequency?

Accepted Answer

A)   UV
B)   X-ray
C)   IR
D)   microwave
E)   visible

Question 5

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

Accepted Answer

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

Question 6

Calculate the degree of unsaturation for C14H14N2O.

Accepted Answer

A)   4
B)   6
C)   8
D)   10
E)   9

Question 7

Calculate the degree of unsaturation for C9H11N.

Accepted Answer

A)   4
B)   6
C)   2
D)   5
E)   3

Question 8

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

Accepted Answer

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

Question 9

Following are the IR spectrum and mass spectrum of an unknown compound. Propose a structure for the unknown compound.   SDBS:

Accepted Answer

The answer of Following are the IR spectrum and mass...

Question 10

Which of the following wavenumber corresponds to the C=O double bond region on an IR spectrum?

Accepted Answer

A)   1500 - 4000 cm-1
B)   400 - 4000 cm-1
C)   400 - 1500 cm-1
D)   2100 - 2300 cm-1
E)   1600 - 1850 cm-1

Question 11

Which of the m/z values correspond to the molecular ion for the following compound?

Accepted Answer

A)   18
B)   82
C)   100
D)   102
E)   103

Question 12

Which of the following vibrations are observed in IR spectroscopy?

Accepted Answer

A)   stretching
B)   rotational
C)   bending
D)   A and B
E)   A and C

Question 13

Which of the following information is primarily obtained from nuclear magnetic resonance spectroscopy?

Accepted Answer

A)   arrangement of carbon and hydrogen atoms in a compound
B)   molecular weight of a compound
C)   any conjugated π system present in a compound
D)   functional groups present in a compound
E)   all of these

Question 14

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 and B
E)   A and C

Question 15

Rank absorption of the indicated bonds in decreasing (highest to lowest)  order of wavenumber.  V > II > IV > III B)  IV > II > I > V > III C)  II > I > V > III > IV D)  IV > I > V > II > III E)  IV > II > V > I > III" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

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

Question 16

In mass spectrometry, the tallest peak is assigned an intensity of 100% and is referred to as the ______________.

Accepted Answer

The answer of In mass spectrometry, the tallest peak is...

Question 17

Provide a molecular formula that is consistent with the following mass spectral data.
M+• at m/z = 136, relative height = 65.6%
(M+1)+ • at m/z = 137, relative height = 6.2%

Accepted Answer

Question 18

Provide a molecular formula that is consistent with the following mass spectral data.
M+• at m/z = 167, relative height = 50.0%
(M+1)+ • at m/z = 168, relative height = 4.4%

Accepted Answer

Question 19

For the following reaction, which of the following change(s)  in the IR spectrum is consistent with conversion of the reactant to the product? -1 should disappear B)  absorption at 3300 - 3400 cm-1 and 1100 cm-1 should disappear C)  absorption at 1100 cm-1 should disappear, a new absorption at 3100 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 - 3400 cm-1 should appear" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   absorption at 3300 - 3400 cm-1 should disappear
B)   absorption at 3300 - 3400 cm-1 and 1100 cm-1 should disappear
C)   absorption at 1100 cm-1 should disappear, a new absorption at 3100 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 - 3400 cm-1 should appear

Question 20

Predict the product for the following reaction and explain how you can use IR spectroscopy to monitor the progress of the reaction.

Accepted Answer

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Exam 14: Infrared Spectroscopy and Mass Spectrometry

Rank absorption of the indicated bonds in decreasing (highest to lowest) order of wavenumber.

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In mass spectrometry using the electron impact ionization technique, a beam of high-energy electrons initially ejects one electron from the compound being studied. This produces a positively charged ion called the ____________________.

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Which molecular formula is consistent with the following mass spectral 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%

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Which of the m/z values correspond to the molecular ion for the following compound?

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In mass spectrometry, the tallest peak is assigned an intensity of 100% and is referred to as the ______________.

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Calculate the degree of unsaturation for C9H11N.

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Provide a molecular formula that is consistent with the following mass spectral data. M+• at m/z = 167, relative height = 50.0% (M+1)+ • at m/z = 168, relative height = 4.4%

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

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Which of the following information is primarily obtained from nuclear magnetic resonance spectroscopy?

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Following are the IR spectrum and mass spectrum of an unknown compound. Propose a structure for the unknown compound. SDBS:

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

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Calculate the degree of unsaturation for C14H14N2O.

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Which of the following electromagnetic radiation has the highest frequency?

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Which of the following wavenumber corresponds to the C=O double bond region on an IR spectrum?

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Provide a molecular formula that is consistent with the following mass spectral data. M+• at m/z = 136, relative height = 65.6% (M+1)+ • at m/z = 137, relative height = 6.2%

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Which of the following is always true about the base peak in a mass spectrum?

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

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Which of the following vibrations are observed in IR spectroscopy?

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Predict the product for the following reaction and explain how you can use IR spectroscopy to monitor the progress of the reaction.

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Mass spectrometry is primarily used to determine:

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Which molecular formula is consistent with the following mass spectral 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%

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Calculate the degree of unsaturation for C₉H₁₁N.

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Provide a molecular formula that is consistent with the following mass spectral data. M⁺•at m/z = 167, relative height = 50.0% (M+1)⁺ •at m/z = 168, relative height = 4.4%

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Calculate the degree of unsaturation for C₁₄H₁₄N₂O.

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Provide a molecular formula that is consistent with the following mass spectral data. M⁺•at m/z = 136, relative height = 65.6% (M+1)⁺ •at m/z = 137, relative height = 6.2%

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_TB4454_00 A new abs...
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