Question 1

Which of the following sets of molecular ions does an alkyl bromide possess?

Accepted Answer

A) two molecular ions in a 2:1 ratio separated by two mass units 
B) two molecular ions in a 1:1 ratio separated by two mass units 
C) three molecular ions in a 1:2:1 ratio separated by two mass units 
D) two molecular ions in a 3:1 ratio separated by two mass units 
A) two molecular ions in a 2:1 ratio separated by two mass units 
B) two molecular ions in a 1:1 ratio separated by two mass units 
C) three molecular ions in a 1:2:1 ratio separated by two mass units 
D) two molecular ions in a 3:1 ratio separated by two mass units

Question 2

Which of the following gives rise to a prominent peak in the mass spectrum with m/z of 41?

Accepted Answer

A) 1-hexene 
B) 2-hexyne 
C) 3-hexanol 
D) 2-chlorohexane 
A) 1-hexene 
B) 2-hexyne 
C) 3-hexanol 
D) 2-chlorohexane

Question 3

Which C6H12O carbonyl-containing compound shows a molecular ion peak at m/z 100 and significant fragment peaks at m/z 71, 58, 57, 43 and 29 in the EI mass spectrum?

Accepted Answer

Question 4

What is the principle that allows us to use mass spectrometry to determine the molecular weight of a compound?

Accepted Answer

A) higher molecular weight compounds are less volatile 
B) higher molecular weight compounds are more dense 
C) a beam of higher molecular weight cations is deflected less by a magnetic field 
D) ions with higher molecular weight absorb higher frequencies of light 
A) higher molecular weight compounds are less volatile 
B) higher molecular weight compounds are more dense 
C) a beam of higher molecular weight cations is deflected less by a magnetic field 
D) ions with higher molecular weight absorb higher frequencies of light

Question 5

In mass spectrometry, which of the following phrases is shortened to the acronym "MALDI"?

Accepted Answer

A) mass analysis by light-detected ions 
B) matrix assisted laser desorption ionization 
C) many atom loss-detecting ionization 
D) molecular and light detecting instrument 
A) mass analysis by light-detected ions 
B) matrix assisted laser desorption ionization 
C) many atom loss-detecting ionization 
D) molecular and light detecting instrument

Question 6

Which of the following alcohols does not give a prominent M - 15 ion?

Accepted Answer

A) isopropyl alcohol 
B) tert-butyl alcohol 
C) 2-hexanol 
D) 3-pentanol 
A) isopropyl alcohol 
B) tert-butyl alcohol 
C) 2-hexanol 
D) 3-pentanol

Question 7

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s).   Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/
-The peak at a m/z of _____ represents the following species.

Accepted Answer

The answer of Refer to the mass spectrum of 2-methylbutane...

Question 8

The following question(s) refer to the mass spectrum shown below.   Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/
-This compound contains C, H, and one other atom. The other atom from the mass spectrum is __________.

Accepted Answer

The answer of The following question(s) refer to the mass...

Question 9

Which of the following gives rise to a prominent M - 18 peak in the mass spectrum?

Accepted Answer

A) cyclohexane 
B) cyclohexene 
C) 1-chlorocyclohexane 
D) cyclohexanol 
A) cyclohexane 
B) cyclohexene 
C) 1-chlorocyclohexane 
D) cyclohexanol

Question 10

What is the most likely molecular formula of a compound that has a molecular ion in the EI mass spectrum with m/z of 97 and an M+1 peak that is 6.6% of the intensity of the molecular ion peak?

Accepted Answer

The answer of What is the most likely molecular formula...

Question 11

Provide the mass of the three most prominent fragment peaks that are observed in the EI mass spectrum of 2-hexanone, CH3CH2CH2CH2COCH3 (molecular ion m/z = 100) and describe the processes that lead to each of these fragments.

Accepted Answer

85: loss of CH₃• (15) by @#LAT-DLM&-cleav

Question 12

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s).   Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/
-Alpha cleavage of the following compound will produce a peak at a m/z of _______.

Accepted Answer

The answer of Refer to the mass spectrum of 2-methylbutane...

Question 13

The following question(s) refer to the mass spectrum shown below.   Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/
-The base peak in this spectrum occurs at a m/z of ______.

Accepted Answer

The answer of The following question(s) refer to the mass...

Question 14

Which of the following gives rise to a prominent M - 18 peak in the mass spectrum?

Accepted Answer

A) hexane 
B) 1-chloropentane 
C) 1-pentanol 
D) 3-methylpentane 
A) hexane 
B) 1-chloropentane 
C) 1-pentanol 
D) 3-methylpentane

Question 15

Which of the following is not prominent in the mass spectrum of 2-methyl-2-butanol?

Accepted Answer

A) M - 29 
B) M- 18 
C) M - 15 
D) M - 12 
A) M - 29 
B) M- 18 
C) M - 15 
D) M - 12

Question 16

Which of the following gives rise to a prominent peak in the mass spectrum with m/z of 91?

Accepted Answer

A) 1-octene 
B) 1-hexanamine, CH3CH2CH2CH2CH2CH2NH2 
C) benzene 
D) ethylbenzene 
A) 1-octene 
B) 1-hexanamine, CH3CH2CH2CH2CH2CH2NH2 
C) benzene 
D) ethylbenzene

Question 17

It is not possible distinguish 2,2-dimethylbutane from 2-methylpentane using mass spectrometry.

Accepted Answer

A) True 
 B)False

Question 18

How many carbon atoms are present in a molecule which gives an M+1 peak that is 5.74% of the intensity of the molecular ion?

Accepted Answer

A) 5 
B) 6 
C) 11 
D) 12 
A) 5 
B) 6 
C) 11 
D) 12

Question 19

A monochloroalkane shows two parent ion peaks m/z at 92 and 94. The molecular formula of this compound might be C3H7Cl.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following is most consistent with a molecule having a molecular ion with m/e of 77?

Accepted Answer

A) the molecule contains bromine 
B) the molecule contains nitrogen 
C) the molecule is an alcohol 
D) the molecule is a hydrocarbon 
A) the molecule contains bromine 
B) the molecule contains nitrogen 
C) the molecule is an alcohol 
D) the molecule is a hydrocarbon

Exam 14: Mass Spectrometry

Which of the following sets of molecular ions does an alkyl bromide possess?

Which of the following gives rise to a prominent peak in the mass spectrum with m/z of 41?

Which C6H12O carbonyl-containing compound shows a molecular ion peak at m/z 100 and significant fragment peaks at m/z 71, 58, 57, 43 and 29 in the EI mass spectrum?

What is the principle that allows us to use mass spectrometry to determine the molecular weight of a compound?

In mass spectrometry, which of the following phrases is shortened to the acronym "MALDI"?

Which of the following alcohols does not give a prominent M - 15 ion?

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s). Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -The peak at a m/z of _____ represents the following species.

The following question(s) refer to the mass spectrum shown below. Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -This compound contains C, H, and one other atom. The other atom from the mass spectrum is __________.

Which of the following gives rise to a prominent M - 18 peak in the mass spectrum?

What is the most likely molecular formula of a compound that has a molecular ion in the EI mass spectrum with m/z of 97 and an M+1 peak that is 6.6% of the intensity of the molecular ion peak?

Provide the mass of the three most prominent fragment peaks that are observed in the EI mass spectrum of 2-hexanone, CH3CH2CH2CH2COCH3 (molecular ion m/z = 100) and describe the processes that lead to each of these fragments.

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s). Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -Alpha cleavage of the following compound will produce a peak at a m/z of _______.

The following question(s) refer to the mass spectrum shown below. Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ -The base peak in this spectrum occurs at a m/z of ______.

Which of the following gives rise to a prominent M - 18 peak in the mass spectrum?

Which of the following is not prominent in the mass spectrum of 2-methyl-2-butanol?

Which of the following gives rise to a prominent peak in the mass spectrum with m/z of 91?

It is not possible distinguish 2,2-dimethylbutane from 2-methylpentane using mass spectrometry.

How many carbon atoms are present in a molecule which gives an M+1 peak that is 5.74% of the intensity of the molecular ion?

A monochloroalkane shows two parent ion peaks m/z at 92 and 94. The molecular formula of this compound might be C3H7Cl.

Which of the following is most consistent with a molecule having a molecular ion with m/e of 77?

Covalent Bonding and Shapes of Molecules

Alkanes and Cycloalkanes

Stereoisomerism and Chirality

Acids and Bases

Alkenes: Bonding, Nomenclature, and Properties

Reactions of Alkenes

Alkynes

Haloalkanes, Halogenation, and Radical Reactions

Nucleophilic Substitution and Beta-Elimination

Alcohols

Ethers, Epoxides, and Sulfides

Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

An Introduction to Organometallic Compounds

Aldehydes and Ketones

Carboxylic Acids

Functional Derivatives of Carboxylic Acids

Enolate Anions and Enamines

Dienes, Conjugated Systems, and Pericyclic Reactions

Benzene and the Concept of Aromaticity

Reactions of Benzene and Its Derivatives

Amines

Catalytic Carbon-Carbon Bond Formation

Carbohydrates

Lipids

Amino Acids and Proteins

Nucleic Acids

Organic Polymer Chemistry

Filters

Which C₆H₁₂O carbonyl-containing compound shows a molecular ion peak at m/z 100 and significant fragment peaks at m/z 71, 58, 57, 43 and 29 in the EI mass spectrum?

Provide the mass of the three most prominent fragment peaks that are observed in the EI mass spectrum of 2-hexanone, CH₃CH₂CH₂CH₂COCH₃ (molecular ion m/z = 100) and describe the processes that lead to each of these fragments.

A monochloroalkane shows two parent ion peaks m/z at 92 and 94. The molecular formula of this compound might be C₃H₇Cl.