Question 1

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

Accepted Answer

CH₃CH₂CH₂C$ \equiv$CCH₂CH₂CH₃ Absorptions for spC-H around 3300 cm^-1 and C$ \equiv$C around 2150 cm^-1 should disappear from the product IR spectrum.

Question 2

Propose possible structure(s) for a compound with molecular formula C4H7N that shows absorption at 2250 cm-1 in its IR spectrum.

Accepted Answer

CH₃CH₂CH₂C$ \equiv$N OR (CH₃)₂CH₂C$ \equiv$N

Question 3

Which of the following electromagnetic radiation has the longest wavelength?

Accepted Answer

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

Question 4

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

Accepted Answer

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

Question 5

Propose a possible structure for a compound with molecular formula C6H5Br.

Accepted Answer

@#IMG-DLM& there are

Question 6

For which of the following compounds will the (M+2)+ .  peak intensity be around one third 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 7

Which of the following mass spectra shows the presence of chlorine 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 8

Which of the following alkene groups will produce the stronger signal? Explain why.

Accepted Answer

Compound I.
The more electrone

Question 9

Which of the following is not true about the molecular ion in mass spectrometry?

Accepted Answer

A)  The molecular ion is produced by loss of one electron from the molecule. 
B)  The mass of the molecular ion is equivalent to the mass of the molecule. 
C)  The ion is produced by a loss of pair of electrons from the molecule. 
D)  The molecular ion is often unstable and can undergo fragmentation. 
E)  none of these 
A)  The molecular ion is produced by loss of one electron from the molecule. 
B)  The mass of the molecular ion is equivalent to the mass of the molecule. 
C)  The ion is produced by a loss of pair of electrons from the molecule. 
D)  The molecular ion is often unstable and can undergo fragmentation. 
E)  none of these

Question 10

Which of the following will produce M+ .  and (M+2)+ . peaks of equal intensity?

Accepted Answer

A)  nitrogen 
B)  chlorine 
C)  bromine 
D)  oxygen 
E)  B & C 
A)  nitrogen 
B)  chlorine 
C)  bromine 
D)  oxygen 
E)  B & C

Question 11

Which of the following is the base peak in the mass spectrum of 2,2,4-trimethylpentane?

Accepted Answer

A)  114 
B)  57 
C)  42 
D)  29 
E)  none of these 
A)  114 
B)  57 
C)  42 
D)  29 
E)  none of these

Question 12

Which of the following compounds will show absorptions at 1640 cm-1, 2950 cm-1 and 3050 cm-1 on the IR spectrum?

Accepted Answer

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

Question 13

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 14

For the following pair of compounds the expected stretching absorption of the C=O bond is 1685cm-1 & 1715cm-1 respectively. Explain using both words and structural drawings.

Accepted Answer

Compound I has a conjugated do

Question 15

The separation of ions in the mass spectrometer is done by their ______.

Accepted Answer

A)  electrons to protons ratio 
B)  mass to neutrons ratio 
C)  protons to neutrons ratio 
D)  mass to charge ratio 
E)  none of these 
A)  electrons to protons ratio 
B)  mass to neutrons ratio 
C)  protons to neutrons ratio 
D)  mass to charge ratio 
E)  none of these

Question 16

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

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)  none of these 
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)  none of these

Question 17

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 18

Rank absorption of 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 19

Which of the following statement(s) is(are) true about the frequency of a stretching vibration according to Hooke'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 20

Diluted alcohols show a _____absorption around 3600cm-1, due to _____.

Accepted Answer

A)  sharp, hydrogen bonding 
B)  broad, hydrogen bonding 
C)  sharp, absence of hydrogen bonding 
D)  broad, absence of hydrogen bonding 
A)  sharp, hydrogen bonding 
B)  broad, hydrogen bonding 
C)  sharp, absence of hydrogen bonding 
D)  broad, absence of hydrogen bonding

Exam 15: Infrared Spectroscopy and Mass Spectrometry

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

Propose possible structure(s) for a compound with molecular formula C4H7N that shows absorption at 2250 cm-1 in its IR spectrum.

Which of the following electromagnetic radiation has the longest wavelength?

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

Propose a possible structure for a compound with molecular formula C6H5Br.

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

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

Which of the following alkene groups will produce the stronger signal? Explain why.

Which of the following is not true about the molecular ion in mass spectrometry?

Which of the following will produce M+ . and (M+2)+ . peaks of equal intensity?

Which of the following is the base peak in the mass spectrum of 2,2,4-trimethylpentane?

Which of the following compounds will show absorptions at 1640 cm-1, 2950 cm-1 and 3050 cm-1 on the IR 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

For the following pair of compounds the expected stretching absorption of the C=O bond is 1685cm-1 & 1715cm-1 respectively. Explain using both words and structural drawings.

The separation of ions in the mass spectrometer is done by their ______.

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

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

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

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

Diluted alcohols show a _____absorption around 3600cm-1, due to _____.

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

Propose possible structure(s) for a compound with molecular formula C₄H₇N that shows absorption at 2250 cm^-1 in its IR spectrum.

Propose a possible structure for a compound with molecular formula C₆H₅Br.

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

Which of the following will produce M⁺ ^. and (M+2)⁺ ^. peaks of equal intensity?

Which of the following compounds will show absorptions at 1640 cm^-1, 2950 cm^-1and 3050 cm^-1 on the IR spectrum?

For the following pair of compounds the expected stretching absorption of the C=O bond is 1685cm^-1& 1715cm^-1 respectively. Explain using both words and structural drawings.

Diluted alcohols show a _absorption around 3600cm^-1, due to _.