Question 1

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

Accepted Answer

A)  The base peak corresponds to the molecular ion.
B)  The base peak corresponds to the most abundant ion.
C)  The base peak corresponds to the lowest m/z.
D)  None of these.E) C) and D)
F) None of the above

Question 2

Heptane,C7H16,would have which of the following fragments in its mass spectrum? m/z
I 29
II 43
III 57

Accepted Answer

A)  I
B)  II
C)  III
D)  All of the choices are correct.E) All of the above
F) None of the above

Question 3

2,3-dimethylbutane gives a base fragment peak at m/z = 43.Which of the following is the most probable structure of the fragment ion?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and D)
F) All of the above

Question 4

In electron impact mass spectrometry (EIMS) ,what is being detected?

Accepted Answer

A)  The molecular mass of the compound
B)  The molecular formula of the compound
C)  The mass to charge ratio of any ionic species
D)  The mass to charge ratio of any neutral speciesE) None of the above
F) All of the above

Question 5

A compound X has a molecular ion peak in its mass spectrum at m/z 136.What information does this tell us about X?

Accepted Answer

A)  X has a molecular mass of 136.
B)  The molecular formula for X is C8H8O2.
C)  The empirical formula for X is C4H4O.
D)  Both A (X has a molecular mass of 136) and B (The molecular formula for X is C8H8O2) are true.
E)  Statements (X has a molecular mass of 136) ,(The molecular formula for X is C8H8O2) ,and (The empirical formula for X is C4H4O) are all true.F) B) and C)
G) B) and E) A

Question 6

What is the molecular ion,m/z,for the following molecule?

Accepted Answer

A)  72
B)  70
C)  68
D)  66E) None of the above
F) All of the above

Question 7

What is the molecular ion,m/z,for the following molecule?

Accepted Answer

A)  72
B)  70
C)  68
D)  66E) All of the above
F) A) and B)

Question 8

Butane,C4H10,would have which of the following fragments in its mass spectrum? m/z
I 15
II 29
III 57

Accepted Answer

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

Question 9

Which of the following alkanes gives a significant fragment peak at m/z = 57?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) All of the above
F) C) and D)

Question 10

Hexane,C6H14,would have which of the following fragments in its mass spectrum? m/z
I 29
II 43
III 57

Accepted Answer

A)  I
B)  II
C)  III
D)  All of the choices are correct.E) B) and C)
F) A) and D)

Question 11

What type of signal(s) would you observe in the mass and (or) infrared spectrum of the following compound?

Accepted Answer

A)  A signal at 95 amu
B)  A signal at 94 amu
C)  Two signals at 95 and 94 amu
D)  A signal at 106 amuE) None of the above
F) All of the above A

Question 12

What would be the molecular formula of rose oxide which contains C,H,and O and has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?

Accepted Answer

A)  C10H18O
B)  C9H14O2
C)  C10H2O2
D)  C8H10O3E) B) and D)
F) All of the above

Question 13

In a typical mass spectrum,a smaller signal is observed at a mass 1 amu higher than the molecular ion peak.Why?

Accepted Answer

A)  Due to small impurities in the sample
B)  Machine error
C)  Because a small percentage of the compound will have a carbon that is the isotope 13C instead of 12C
D)  Because of fragmentationE) B) and C)
F) A) and C)

Question 14

You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at 162,both of equal intensity.This compound contains

Accepted Answer

A)  two chlorine atoms.
B)  one iodine atom.
C)  one bromine atom.
D)  two bromine atoms.E) B) and C)
F) C) and D) C

Question 15

2,2-dimethylbutane gives a significant fragment peak at m/z = 57.Which of the following is the most probable structure of the fragment ion?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and C)
F) None of the above

Question 16

What is the molecular ion,m/z,for the following molecule?

Accepted Answer

A)  72
B)  70
C)  68
D)  66E) A) and C)
F) A) and B)

Question 17

What type of feature will be observed in the EI mass spectrum of chlorobenzene?

Accepted Answer

A)  An absorption at 3100 cm-1
B)  A signal at 113
C)  A signal at 112 and a signal at 114 in a ratio of 3:1
D)  A signal at 112 and a signal at 114 in a ratio of 1:1E) C) and D)
F) A) and B)

Question 18

What is the molecular ion,m/z,for the following molecule?

Accepted Answer

A)  72
B)  70
C)  68
D)  66E) A) and C)
F) A) and B)

Question 19

Pentane,C5H12,would have which of the following fragments in its mass spectrum? m/z
II 29
III 43
IV 57

Accepted Answer

A)  I
B)  II
C)  III
D)  All of the choices are correct.E) A) and C)
F) B) and C)

Exam 30: Molecular Ion Peaks and Fragmentation Patterns

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

Correct Answer
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Heptane,C₇H₁₆,would have which of the following fragments in its mass spectrum? m/z I 29 II 43 III 57

Correct Answer
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2,3-dimethylbutane gives a base fragment peak at m/z = 43.Which of the following is the most probable structure of the fragment ion?

Correct Answer
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In electron impact mass spectrometry (EIMS) ,what is being detected?

Correct Answer
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A compound X has a molecular ion peak in its mass spectrum at m/z 136.What information does this tell us about X?

Correct Answer
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A

What is the molecular ion,m/z,for the following molecule?

Correct Answer
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What is the molecular ion,m/z,for the following molecule?

Correct Answer
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Butane,C₄H₁₀,would have which of the following fragments in its mass spectrum? m/z I 15 II 29 III 57

Correct Answer
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Which of the following alkanes gives a significant fragment peak at m/z = 57?

Correct Answer
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Hexane,C₆H₁₄,would have which of the following fragments in its mass spectrum? m/z I 29 II 43 III 57

Correct Answer
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What type of signal(s) would you observe in the mass and (or) infrared spectrum of the following compound?

Correct Answer
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A

What would be the molecular formula of rose oxide which contains C,H,and O and has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?

Correct Answer
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In a typical mass spectrum,a smaller signal is observed at a mass 1 amu higher than the molecular ion peak.Why?

Correct Answer
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You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at 162,both of equal intensity.This compound contains

Correct Answer
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C

2,2-dimethylbutane gives a significant fragment peak at m/z = 57.Which of the following is the most probable structure of the fragment ion?

Correct Answer
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What is the molecular ion,m/z,for the following molecule?

Correct Answer
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What type of feature will be observed in the EI mass spectrum of chlorobenzene?

Correct Answer
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What is the molecular ion,m/z,for the following molecule?

Correct Answer
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Pentane,C₅H₁₂,would have which of the following fragments in its mass spectrum? m/z II 29 III 43 IV 57

Correct Answer
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Exam 30: Molecular Ion Peaks and Fragmentation Patterns

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

Correct AnswerverifiedShow Answer

Heptane,C7H16,would have which of the following fragments in its mass spectrum? m/z I 29 II 43 III 57

Correct AnswerverifiedShow Answer

2,3-dimethylbutane gives a base fragment peak at m/z = 43.Which of the following is the most probable structure of the fragment ion?

Correct AnswerverifiedShow Answer

In electron impact mass spectrometry (EIMS) ,what is being detected?

Correct AnswerverifiedShow Answer

A compound X has a molecular ion peak in its mass spectrum at m/z 136.What information does this tell us about X?

Correct AnswerverifiedA

What is the molecular ion,m/z,for the following molecule?

Correct AnswerverifiedShow Answer

What is the molecular ion,m/z,for the following molecule?

Correct AnswerverifiedShow Answer

Butane,C4H10,would have which of the following fragments in its mass spectrum? m/z I 15 II 29 III 57

Correct AnswerverifiedShow Answer

Which of the following alkanes gives a significant fragment peak at m/z = 57?

Correct AnswerverifiedShow Answer

Hexane,C6H14,would have which of the following fragments in its mass spectrum? m/z I 29 II 43 III 57

Correct AnswerverifiedShow Answer

What type of signal(s) would you observe in the mass and (or) infrared spectrum of the following compound?

Correct AnswerverifiedA

What would be the molecular formula of rose oxide which contains C,H,and O and has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?

Correct AnswerverifiedShow Answer

In a typical mass spectrum,a smaller signal is observed at a mass 1 amu higher than the molecular ion peak.Why?

Correct AnswerverifiedShow Answer

You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at 162,both of equal intensity.This compound contains

Correct AnswerverifiedC

2,2-dimethylbutane gives a significant fragment peak at m/z = 57.Which of the following is the most probable structure of the fragment ion?

Correct AnswerverifiedShow Answer

What is the molecular ion,m/z,for the following molecule?

Correct AnswerverifiedShow Answer

What type of feature will be observed in the EI mass spectrum of chlorobenzene?

Correct AnswerverifiedShow Answer

What is the molecular ion,m/z,for the following molecule?

Correct AnswerverifiedShow Answer

Pentane,C5H12,would have which of the following fragments in its mass spectrum? m/z II 29 III 43 IV 57

Correct AnswerverifiedShow Answer

Correct Answer
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Heptane,C₇H₁₆,would have which of the following fragments in its mass spectrum? m/z I 29 II 43 III 57

Correct Answer
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A

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Butane,C₄H₁₀,would have which of the following fragments in its mass spectrum? m/z I 15 II 29 III 57

Correct Answer
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Correct Answer
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Hexane,C₆H₁₄,would have which of the following fragments in its mass spectrum? m/z I 29 II 43 III 57

Correct Answer
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A

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C

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Pentane,C₅H₁₂,would have which of the following fragments in its mass spectrum? m/z II 29 III 43 IV 57

Correct Answer
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