Question 1

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1630-1820 cm-1 (strong, broad) and 1000-1250 cm-1; but does not have peaks at 3200-3650 cm-1?

Accepted Answer

A)   alcohol
B)   aldehyde or ketone
C)   ether
D)   ester D

Question 2

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of N,N-dimethylacetamide, CH₃CON(CH₃)₂, is higher than that of methyl acetate, CH₃CO₂CH₃.

Accepted Answer

The C=O bond of the amide is weaker than that of the ester. Nitrogen is less electronegative than oxygen, and therefore a better electron pair donor. Accordingly, the resonance contributor in which the nitrogen has donated a pair of electrons to the carbonyl carbon atom is an important contributor to the structure.

Question 3

Which of the following compounds gives an infrared spectrum with no significant peaks at ~3300 cm-1 or 1600-1680 cm-1?

Accepted Answer

A)   1
B)   2
C)   3
D)   4 B

Question 4

Which of the following compounds gives a carbonyl bond absorption at the lowest frequency?

Accepted Answer

A)   1
B)   2
C)   3
D)   4

Question 5

Which of the following compounds gives an infrared spectrum with peaks at 3000-3500 cm-1 and ~1750 cm-1?

Accepted Answer

A)   1
B)   2
C)   3
D)   4

Question 6

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the longest wavelength?

Accepted Answer

A)   radio waves
B)   ultraviolet
C)   infrared
D)   visible

Question 7

Which of the following processes takes place upon absorption of infrared radiation?

Accepted Answer

A)   bond vibration
B)   electron excitation
C)   nuclear spin flip
D)   electron spin flip

Question 8

What range of wavelengths corresponds to the infrared region of the electromagnetic spectrum?

Accepted Answer

A)   200-400 nm
B)   400-700 nm
C)   2.5-50 mm
D)   2-10 mm

Question 9

Which of the following compounds gives an infrared spectrum with peaks in the ranges of 3200-3650 (strong, broad) and 1600-1640 cm-1 (medium); but does not have peaks at 1630-1820 (strong)?

Accepted Answer

A)   1
B)   2
C)   3
D)   4

Question 10

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1000-1250 cm-1 (strong), but does not have peaks 3200-3650 at 1630-1820 or cm-1?

Accepted Answer

A)   alcohol
B)   aldehyde or ketone
C)   ether
D)   ester

Question 11

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₅H₁₀O₂)?

Accepted Answer

The answer of Label three peaks in the following spectrum...

Question 12

Which of the following bonds gives rise to a strong, broad, absorbance at approximately 3200-3650 cm-1 in the infrared spectrum?

Accepted Answer

A)   C=O
B)   O-H
C)   C=C
D)   C-H

Question 13

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₆H₁₄O)?

Accepted Answer

The answer of Label three peaks in the following spectrum...

Question 14

What are the units of wavenumber,  , in infrared spectroscopy?

Accepted Answer

A)   cm
B)   cm-1
C)   J*mol-1
D)   none, wavenumber is a dimensionless quantity

Question 15

Which of the following bonds gives the weakest peak in the infrared spectrum for a stretching vibration?

Accepted Answer

A)   1
B)   2
C)   3
D)   4

Question 16

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₄H₉NO)?

Accepted Answer

The answer of Label three peaks in the following spectrum...

Question 17

Which of the following carbon-carbon bonds undergoes stretching at the highest frequency?

Accepted Answer

A)   sp3 C - sp3 C
B)   alkene sp2 C - sp2 C
C)   arene sp2 C - sp2 C
D)   CºC

Question 18

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of 2-butanone is higher than that of 3-buten-2-one.

Accepted Answer

The answer of Provide a brief explanation to account for...

Question 19

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm-1 (sharp peak) and 2150 cm-1 (sharp peak)?

Accepted Answer

A)   1
B)   2
C)   3
D)   4

Question 20

Provide the structure of three compounds with the molecular formula C₄H₈O that give an absorption peak at 1600-1640 cm^-1 in the infrared spectrum, but no significant peaks at 3000-3600 cm^-1 or at 1650-1750 cm^-1.

Accepted Answer

The answer of Provide the structure of three compounds with...

Exam 12: Infrared Spectroscopy

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1630-1820 cm^-1 (strong, broad) and 1000-1250 cm^-1; but does not have peaks at 3200-3650 cm^-1?

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of N,N-dimethylacetamide, CH₃CON(CH₃)₂, is higher than that of methyl acetate, CH₃CO₂CH₃.

Which of the following compounds gives an infrared spectrum with no significant peaks at ~3300 cm^-1 or 1600-1680 cm^-1?

Which of the following compounds gives a carbonyl bond absorption at the lowest frequency?

Which of the following compounds gives an infrared spectrum with peaks at 3000-3500 cm^-1 and ~1750 cm^-1?

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the longest wavelength?

Which of the following processes takes place upon absorption of infrared radiation?

What range of wavelengths corresponds to the infrared region of the electromagnetic spectrum?

Which of the following compounds gives an infrared spectrum with peaks in the ranges of 3200-3650 (strong, broad) and 1600-1640 cm^-1 (medium) ; but does not have peaks at 1630-1820 (strong) ?

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1000-1250 cm^-1 (strong) , but does not have peaks 3200-3650 at 1630-1820 or cm^-1?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₅H₁₀O₂)?

Which of the following bonds gives rise to a strong, broad, absorbance at approximately 3200-3650 cm^-1 in the infrared spectrum?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₆H₁₄O)?

What are the units of wavenumber, , in infrared spectroscopy?

Which of the following bonds gives the weakest peak in the infrared spectrum for a stretching vibration?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₄H₉NO)?

Which of the following carbon-carbon bonds undergoes stretching at the highest frequency?

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of 2-butanone is higher than that of 3-buten-2-one.

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm^-1 (sharp peak) and 2150 cm^-1 (sharp peak) ?

Provide the structure of three compounds with the molecular formula C₄H₈O that give an absorption peak at 1600-1640 cm^-1 in the infrared spectrum, but no significant peaks at 3000-3600 cm^-1 or at 1650-1750 cm^-1.

Exam 12: Infrared Spectroscopy

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1630-1820 cm-1 (strong, broad) and 1000-1250 cm-1; but does not have peaks at 3200-3650 cm-1?

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of N,N-dimethylacetamide, CH3CON(CH3)2, is higher than that of methyl acetate, CH3CO2CH3.

Which of the following compounds gives an infrared spectrum with no significant peaks at ~3300 cm-1 or 1600-1680 cm-1?

Which of the following compounds gives a carbonyl bond absorption at the lowest frequency?

Which of the following compounds gives an infrared spectrum with peaks at 3000-3500 cm-1 and ~1750 cm-1?

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the longest wavelength?

Which of the following processes takes place upon absorption of infrared radiation?

What range of wavelengths corresponds to the infrared region of the electromagnetic spectrum?

Which of the following compounds gives an infrared spectrum with peaks in the ranges of 3200-3650 (strong, broad) and 1600-1640 cm-1 (medium) ; but does not have peaks at 1630-1820 (strong) ?

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1000-1250 cm-1 (strong) , but does not have peaks 3200-3650 at 1630-1820 or cm-1?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C5H10O2)?

Which of the following bonds gives rise to a strong, broad, absorbance at approximately 3200-3650 cm-1 in the infrared spectrum?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C6H14O)?

What are the units of wavenumber, , in infrared spectroscopy?

Which of the following bonds gives the weakest peak in the infrared spectrum for a stretching vibration?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C4H9NO)?

Which of the following carbon-carbon bonds undergoes stretching at the highest frequency?

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of 2-butanone is higher than that of 3-buten-2-one.

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm-1 (sharp peak) and 2150 cm-1 (sharp peak) ?

Provide the structure of three compounds with the molecular formula C4H8O that give an absorption peak at 1600-1640 cm-1 in the infrared spectrum, but no significant peaks at 3000-3600 cm-1 or at 1650-1750 cm-1.

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1630-1820 cm^-1 (strong, broad) and 1000-1250 cm^-1; but does not have peaks at 3200-3650 cm^-1?

Provide a brief explanation to account for the observation that the frequency of the C=O stretching absorption in the infrared spectrum of N,N-dimethylacetamide, CH₃CON(CH₃)₂, is higher than that of methyl acetate, CH₃CO₂CH₃.

Which of the following compounds gives an infrared spectrum with no significant peaks at ~3300 cm^-1 or 1600-1680 cm^-1?

Which of the following compounds gives an infrared spectrum with peaks at 3000-3500 cm^-1 and ~1750 cm^-1?

Which of the following compounds gives an infrared spectrum with peaks in the ranges of 3200-3650 (strong, broad) and 1600-1640 cm^-1 (medium) ; but does not have peaks at 1630-1820 (strong) ?

Which of the following functional groups is likely to be present in a molecule that has peaks in the infrared spectrum at 1000-1250 cm^-1 (strong) , but does not have peaks 3200-3650 at 1630-1820 or cm^-1?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₅H₁₀O₂)?

Which of the following bonds gives rise to a strong, broad, absorbance at approximately 3200-3650 cm^-1 in the infrared spectrum?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₆H₁₄O)?

Label three peaks in the following spectrum with the bond that gives rise to them, and identify the functional group that is present in the compound (the compound has a formula of C₄H₉NO)?

Which of the following compounds gives an infrared spectrum with peaks at 3300 cm^-1 (sharp peak) and 2150 cm^-1 (sharp peak) ?

Provide the structure of three compounds with the molecular formula C₄H₈O that give an absorption peak at 1600-1640 cm^-1 in the infrared spectrum, but no significant peaks at 3000-3600 cm^-1 or at 1650-1750 cm^-1.