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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)? 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 C<sub>4</sub>H<sub>9</sub>NO)?

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N-H: ~3500 cm-1
C-H: ...

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Which of the following compounds gives an infrared spectrum with peaks at 3300 cm-1 (sharp peak) and 2150 cm-1 (sharp peak) ? Which of the following compounds gives an infrared spectrum with peaks at 3300 cm<sup>-1</sup> (sharp peak)  and 2150 cm<sup>-1</sup> (sharp peak) ?   A)  1 B)  2 C)  3 D)  4


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

E) A) and B)
F) C) and D)

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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)? 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 C<sub>5</sub>H<sub>10</sub>O<sub>2</sub>)?

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O-H: 3000-3600 cm-1
C-...

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Which of the following compounds gives a carbonyl bond absorption at the lowest frequency? Which of the following compounds gives a carbonyl bond absorption at the lowest frequency?   A)  1 B)  2 C)  3 D)  4


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

E) B) and C)
F) A) and B)

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


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

E) B) and D)
F) B) and C)

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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?


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

E) C) and D)
F) None of the above

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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 no significant peaks at ~3300 cm<sup>-1</sup> or 1600-1680 cm<sup>-1</sup>?   A)  1 B)  2 C)  3 D)  4


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

E) None of the above
F) All of the above

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B

Which of the following bonds gives the weakest peak in the infrared spectrum for a stretching vibration? Which of the following bonds gives the weakest peak in the infrared spectrum for a stretching vibration?   A)  1 B)  2 C)  3 D)  4


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

E) B) and D)
F) B) and C)

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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.

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Any three ...

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


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

E) C) and D)
F) A) and B)

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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.

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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. 11eb135c_c776_7459_8021_575f2aab0b71_TB7077_00

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


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

E) A) and D)
F) None of the above

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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 at 3000-3500 cm<sup>-1</sup> and ~1750 cm<sup>-1</sup>?   A)  1 B)  2 C)  3 D)  4


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

E) B) and D)
F) A) and B)

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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 C<sub>6</sub>H<sub>14</sub>O)?

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O-H: ~3300 cm-1
C-H: ~...

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What are the units of wavenumber, What are the units of wavenumber,   , in infrared spectroscopy? A)  cm B)  cm<sup>-1</sup> C)  J*mol<sup>-1</sup> D)  none, wavenumber is a dimensionless quantity , in infrared spectroscopy?


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

E) C) and D)
F) A) and D)

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


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

E) All of the above
F) B) and D)

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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?


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

E) A) and B)
F) None of the above

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D

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


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

E) A) and D)
F) B) and D)

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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 compounds gives an infrared spectrum with peaks in the ranges of 3200-3650 (strong, broad)  and 1600-1640 cm<sup>-1</sup> (medium) ; but does not have peaks at 1630-1820 (strong) ?   A)  1 B)  2 C)  3 D)  4


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

E) None of the above
F) All of the above

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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.

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The C=O bond of 3-buten-2-one ...

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