Question 1

The radio wave region of the electromagnetic spectrum would have sufficient energy to produce the following energy transition.

Accepted Answer

The answer of The radio wave region of the electromagnetic...

Question 2

Provide the structure of four compounds with the molecular formula C₅H₁₀O which give a strong absorption peak at 1700-1740 cm^-1 in the infrared spectrum, but no significant peaks at 1600-1640 cm^-1 .

Accepted Answer

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

Question 3

MATCH a structure from the list below to the following IR spectra. Place the letter of the structure in the blank provided.
-_____  Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/

Accepted Answer

The answer of MATCH a structure from the list below...

Question 4

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type.
-_____ N−H, C−H, and O−H stretching and bending motions.

Accepted Answer

N−H, C−H, and O−H stretching and bending motions typically occur in the 4000 to 2500 cm^-1 region of the infrared spectrum, which corresponds to the higher energy vibrations of these bonds.

Question 5

he amount of energy in infrared light corresponds to the amount of energy needed to increase certain molecular motions, such as bond vibrations, in organic molecules.

Accepted Answer

Infrared light has the right amount of energy to excite molecular motions in organic molecules, including bond vibrations and rotations, which is fundamental to infrared spectroscopy.

Question 6

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type.
-_____ triple bond stretching vibrations.

Accepted Answer

Triple bond stretching vibrations typically absorb in the region of 2500 to 2000 cm^-1 in the infrared spectrum.

Question 7

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 8

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...

Question 9

In terms of the electromagnetic spectrum, 2870 cm−¹ represents lower energy than 2.91 × 10¹⁶ Hz.

Accepted Answer

The wavenumber 2870 cm⁻¹ corresponds to infrared radiation, which has lower energy than the frequency 2.91 × 10¹⁶ Hz, corresponding to ultraviolet or X-ray radiation.

Question 10

MATCH each of the following molecules to the region of the infrared spectrum in which they may show a significant absorption. Place the letter of the region in the blank to the left of the bond-type.
-_______ $\mathrm{H}_{3} \mathrm{C}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$

Accepted Answer

The molecule has a carbon-carbon triple bond ($\mathrm{C} \equiv \mathrm{C}$), which typically shows significant absorption in the region of 2500 to 2000 cm$^{-1}$ in the infrared spectrum.

Question 11

MATCH a structure from the list below to the following IR spectra. Place the letter of the structure in the blank provided.
-_____  Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/

Accepted Answer

The answer of MATCH a structure from the list below...

Question 12

MATCH each of the following molecules to the region of the infrared spectrum in which they may show a significant absorption. Place the letter of the region in the blank to the left of the bond-type.
-_______

Accepted Answer

The answer of MATCH each of the following molecules to...

Question 13

MATCH each of the following molecules to the region of the infrared spectrum in which they may show a significant absorption. Place the letter of the region in the blank to the left of the bond-type. -_______ CH₃CH₂OCH(CH₃)

Accepted Answer

The C-O bond in CH3CH2OCH(CH3) will show a significant absorption in the region below 1500 cm−1.

Question 14

The vertical axis on an IR spectrum represents the percent transmission and the horizontal axis measures frequency (wavenumber).

Accepted Answer

The vertical axis of an IR spectrum indeed represents the percent transmission, indicating how much of the infrared light is transmitted through the sample, while the horizontal axis measures the frequency of the IR light, typically expressed in wavenumbers (inverse centimeters, cm^-1), which corresponds to the different vibrational modes of the molecules in the sample.

Question 15

MATCH a structure from the list below to the following IR spectra. Place the letter of the structure in the blank provided.
-_____  Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/

Accepted Answer

The answer of MATCH a structure from the list below...

Question 16

Provide a brief explanation to account for the observation that 1-butyne gives a significantly stronger peak at ∼1250 cm^-1 in the infrared spectrum than 2-butyne..

Accepted Answer

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

Question 17

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type.
-_____ C=O, C=N, and C=C bond absorptions.

Accepted Answer

C=O, C=N, and C=C bond absorptions typically occur in the region of 2000 to 1500 cm^-1 in the infrared spectrum, which is known for multiple bond stretches.

Question 18

Examining the infrared spectrum of a compound allows us to determine the nature of the conjugated pi electron system in the compound.

Accepted Answer

Infrared spectroscopy is used to identify functional groups based on bond vibrations, not to analyze conjugated pi electron systems, which are better studied using UV-Vis spectroscopy.

Question 19

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type.
-_____ C−C, C−O, C−N, and C−X single-bond vibrations.

Accepted Answer

C−C, C−O, C−N, and C−X single-bond vibrations typically occur in the region below 1500 cm^−1 in the infrared spectrum. This region is known for fingerprint regions where complex vibrations occur, including bending and stretching of single bonds.

Question 20

A C=O bond undergoes stretching at a lower frequency than C=C.

Accepted Answer

A C=O bond undergoes stretching at a higher frequency than C=C because the C=O bond is stronger and more polarized than the C=C bond, leading to higher vibrational frequencies.

Quiz 12: Infrared Spectroscopy

The radio wave region of the electromagnetic spectrum would have sufficient energy to produce the following energy transition.

Provide the structure of four compounds with the molecular formula C5H10O which give a strong absorption peak at 1700-1740 cm-1 in the infrared spectrum, but no significant peaks at 1600-1640 cm-1 .

MATCH a structure from the list below to the following IR spectra. Place the letter of the structure in the blank provided. -_____ Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type. -_____ N−H, C−H, and O−H stretching and bending motions.

he amount of energy in infrared light corresponds to the amount of energy needed to increase certain molecular motions, such as bond vibrations, in organic molecules.

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type. -_____ triple bond stretching vibrations.

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.

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.

In terms of the electromagnetic spectrum, 2870 cm−1 represents lower energy than 2.91 × 1016 Hz.

MATCH a structure from the list below to the following IR spectra. Place the letter of the structure in the blank provided. -_____ Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/

MATCH each of the following molecules to the region of the infrared spectrum in which they may show a significant absorption. Place the letter of the region in the blank to the left of the bond-type. -_______

MATCH each of the following molecules to the region of the infrared spectrum in which they may show a significant absorption. Place the letter of the region in the blank to the left of the bond-type. -_______ CH3CH2OCH(CH3)

The vertical axis on an IR spectrum represents the percent transmission and the horizontal axis measures frequency (wavenumber).

MATCH a structure from the list below to the following IR spectra. Place the letter of the structure in the blank provided. -_____ Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/

Provide a brief explanation to account for the observation that 1-butyne gives a significantly stronger peak at ∼1250 cm-1 in the infrared spectrum than 2-butyne..

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type. -_____ C=O, C=N, and C=C bond absorptions.

Examining the infrared spectrum of a compound allows us to determine the nature of the conjugated pi electron system in the compound.

MATCH each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. Place the letter of the region in the blank to the left of the bond-type. -_____ C−C, C−O, C−N, and C−X single-bond vibrations.

A C=O bond undergoes stretching at a lower frequency than C=C.

Provide the structure of four compounds with the molecular formula C₅H₁₀O which give a strong absorption peak at 1700-1740 cm^-1 in the infrared spectrum, but no significant peaks at 1600-1640 cm^-1 .

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.

In terms of the electromagnetic spectrum, 2870 cm−¹ represents lower energy than 2.91 × 10¹⁶ Hz.

MATCH each of the following molecules to the region of the infrared spectrum in which they may show a significant absorption. Place the letter of the region in the blank to the left of the bond-type. -_______ CH₃CH₂OCH(CH₃)

Provide a brief explanation to account for the observation that 1-butyne gives a significantly stronger peak at ∼1250 cm^-1 in the infrared spectrum than 2-butyne..