Question 1

Which of the following statement(s)is(are)true about the frequency of a stretching vibration according to Hook's law?

Accepted Answer

A) it is directly proportional to strength of the bond & the reduced mass 
B) it is inversely proportional to strength of the bond & the reduced mass 
C) it is directly proportional to strength of the bond 
D) it is inversely proportional to the reduced mass 
E) C & D 
A) it is directly proportional to strength of the bond & the reduced mass 
B) it is inversely proportional to strength of the bond & the reduced mass 
C) it is directly proportional to strength of the bond 
D) it is inversely proportional to the reduced mass 
E) C & D

Question 2

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 3

Which of the following is expected to be the base peak in the mass spectrum of CH3CH2NH2?

Accepted Answer

A) 15 
B) 28 
C) 30 
D) 45 
E) none of these 
A) 15 
B) 28 
C) 30 
D) 45 
E) none of these

Question 4

Which of the following compounds will show absorption at 2250 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 5

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

Accepted Answer

C<sub>8</s

Question 6

Provide the structure of the major fragment that results when the molecular ion of
(CH3)2CHCH2CH2NH2 undergoes fragmentation.

Accepted Answer

Question 7

Which of the following compounds will produce a prominent (M-18)peak in the mass spectrum?

Accepted Answer

A) 2-methylheptane 
B) 1-heptanol 
C) heptanamine 
D) heptanal 
E) none of these 
A) 2-methylheptane 
B) 1-heptanol 
C) heptanamine 
D) heptanal 
E) none of these

Question 8

Which of the following mass spectra shows the presence of bromine in a compound?     I II     III IV Four spectra above: courtesy of SDBS: National Institute of Advanced Industrial Science and Technology

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 9

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

Accepted Answer

CH₃CH₂CH

Question 10

A compound with molecular formula C3H9N,shows absorptions at 3400 cm-1 (two),2980 cm-1 and at 1100 cm-1 on the IR spectrum.Propose a possible structure for this compound.

Accepted Answer

Question 11

Provide the structures of the fragments that result when the molecular ion of 2-heptanone undergoes fragmentation via McLafferty rearrangement.

Accepted Answer

The answer of Provide the structures of the fragments that...

Question 12

Which of the following bonds would produce the strongest absorption?

Accepted Answer

A) C=N 
B) C$ \equiv$  C 
C) C=O 
D) sp2C-H 
E) C-O 
A) C=N 
B) C$ \equiv$  C 
C) C=O 
D) sp2C-H 
E) C-O

Question 13

For which of the following compounds will the (M+2)+ . peak intensity be around 25% of the intensity of the molecular ion peak?

Accepted Answer

A) CH3CH2CH2Br 
B) CH3CH2CH2OH 
C) CH3CH2CH2Cl 
D) CH3CH2CH2NH2 
E) none of these 
A) CH3CH2CH2Br 
B) CH3CH2CH2OH 
C) CH3CH2CH2Cl 
D) CH3CH2CH2NH2 
E) none of these

Question 14

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 15

Propose a possible structure for a compound with molecular formula C6H5Br

Accepted Answer

Question 16

For the following reaction,which of the following is consistent with the IR spectrum of the product?

Accepted Answer

A) absorption at 3200-3600 cm-1 should disappear 
B) absorption at 3200-3600 cm-1 and 1100 cm-1 should disappear 
C) absorption at 1100 cm-1 should disappear and absorption at 3100 cm-1 should appear 
D) absorption at 1650 cm-1 should disappear and absorption at 3300 cm-1 should appear. 
E) none of these 
A) absorption at 3200-3600 cm-1 should disappear 
B) absorption at 3200-3600 cm-1 and 1100 cm-1 should disappear 
C) absorption at 1100 cm-1 should disappear and absorption at 3100 cm-1 should appear 
D) absorption at 1650 cm-1 should disappear and absorption at 3300 cm-1 should appear. 
E) none of these

Question 17

Which of the following compounds will show a 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 18

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

Accepted Answer

A) CH3CH2CH(CH3)2 
B) CH3CHOHCH2CH3 
C) CH3CH2OCH2CH3 
D) CH3CH2NHCH2CH3 
E) none of these 
A) CH3CH2CH(CH3)2 
B) CH3CHOHCH2CH3 
C) CH3CH2OCH2CH3 
D) CH3CH2NHCH2CH3 
E) none of these

Question 19

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

Accepted Answer

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

Question 20

Which of the m/z values corresponds to the base 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

Exam 15: Infrared Spectroscopy and Mass Spectrometry

Which of the following statement(s)is(are)true about the frequency of a stretching vibration according to Hook's law?

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 is expected to be the base peak in the mass spectrum of CH3CH2NH2?

Which of the following compounds will show absorption at 2250 cm-1?

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

Provide the structure of the major fragment that results when the molecular ion of (CH3)2CHCH2CH2NH2 undergoes fragmentation.

Which of the following compounds will produce a prominent (M-18)peak in the mass spectrum?

Which of the following mass spectra shows the presence of bromine in a compound? I II III IV Four spectra above: courtesy of SDBS: National Institute of Advanced Industrial Science and Technology

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

A compound with molecular formula C3H9N,shows absorptions at 3400 cm-1 (two),2980 cm-1 and at 1100 cm-1 on the IR spectrum.Propose a possible structure for this compound.

Provide the structures of the fragments that result when the molecular ion of 2-heptanone undergoes fragmentation via McLafferty rearrangement.

Which of the following bonds would produce the strongest absorption?

For which of the following compounds will the (M+2)+ . peak intensity be around 25% of the intensity of the molecular ion peak?

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

Propose a possible structure for a compound with molecular formula C6H5Br

For the following reaction,which of the following is consistent with the IR spectrum of the product?

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

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

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

Which of the m/z values corresponds to the base peak in the following mass 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

Filters

Which of the following is expected to be the base peak in the mass spectrum of CH₃CH₂NH₂?

Which of the following compounds will show absorption at 2250 cm^-1?

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

Provide the structure of the major fragment that results when the molecular ion of (CH₃)₂CHCH₂CH₂NH₂ undergoes fragmentation.

A compound with molecular formula C₃H₉N,shows absorptions at 3400 cm^-1 (two),2980 cm^-1 and at 1100 cm^-1 on the IR spectrum.Propose a possible structure for this compound.

For which of the following compounds will the (M+2)⁺ ^. peak intensity be around 25% of the intensity of the molecular ion peak?

Propose a possible structure for a compound with molecular formula C₆H₅Br

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