Question 1

Which of the following functional groups typically exhibits a carbonyl stretch at the lowest frequency?

Accepted Answer

A) amide 
B) ester 
C) ketone 
D) aldehyde 
E) ether 
A) amide 
B) ester 
C) ketone 
D) aldehyde 
E) ether

Question 2

In the mass spectrum of 1,2-dichloroethane, what is the m/z of the molecular ion peak of greatest intensity?

Accepted Answer

A) 94 
B) 96 
C) 98 
D) 100 
E) 102 
A) 94 
B) 96 
C) 98 
D) 100 
E) 102

Question 3

At what wavenumber will the C-H stretch involving an sp carbon appear?

Accepted Answer

A) 2700 cm-1 
B) 2900 cm-1 
C) 3100 cm-1 
D) 3300 cm-1 
E) 3500 cm-1 
A) 2700 cm-1 
B) 2900 cm-1 
C) 3100 cm-1 
D) 3300 cm-1 
E) 3500 cm-1

Question 4

Deduce a possible structure for the compound with the IR absorptions below.
C5H8O: 3000, 1750 cm-1

Accepted Answer

Question 5

Which of the following carbonyl groups exhibits the highest wavenumber in infrared spectroscopy?

Accepted Answer

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

Question 6

An infrared wavelength of 4.48μm is equivalent to a wavenumber of ________ cm-1.

Accepted Answer

Question 7

Which of the following compounds exhibits the highest λmax in UV spectra?

Accepted Answer

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

Question 8

Which has a lower characteristic stretching frequency, the C=O bond or the C-O bond? Explain briefly.

Accepted Answer

Stronger bonds are generally s

Question 9

Which has the higher speed in a vacuum, ultraviolet or infrared light?

Accepted Answer

They have

Question 10

Identify the compound with the longest λmax in an UV spectrum.

Accepted Answer

A) benzene 
B) phenol 
C) phenolate ion 
D) aniline 
E) anilinium ion 
A) benzene 
B) phenol 
C) phenolate ion 
D) aniline 
E) anilinium ion

Question 11

Absorption of UV-visible energy by a molecule results in ________.

Accepted Answer

A) vibrational transitions 
B) electronic transitions 
C) rotational transitions 
D) nuclear transitions 
E) none of the above 
A) vibrational transitions 
B) electronic transitions 
C) rotational transitions 
D) nuclear transitions 
E) none of the above

Question 12

Which compound's C≡C IR band is weakest, 1-butyne, 2-pentyne, or 3-hexyne? Why?

Accepted Answer

The C≡C band of 3-hexyne is we

Question 13

Which of the following species has a characteristic absorption at 2200 cm-1 in its IR spectrum?

Accepted Answer

A) PhCH2CN 
B) PhCH2N(CH3)2 
C) PhCH2CO2CH3 
D) PhCH2CH2OH 
E) PhCH2OCH3 
A) PhCH2CN 
B) PhCH2N(CH3)2 
C) PhCH2CO2CH3 
D) PhCH2CH2OH 
E) PhCH2OCH3

Question 14

Identify the bond with the lowest wavenumber in the IR spectrum.

Accepted Answer

A) C=O 
B) C-O 
C) O-H in alcohol 
D) N-H 
E) C-H 
A) C=O 
B) C-O 
C) O-H in alcohol 
D) N-H 
E) C-H

Question 15

Describe the fate of a molecule from introduction to detection in a mass spectrometer.

Accepted Answer

Upon introduction, sample molecules are

Question 16

Which of the following is true about the base peak in mass spectrometry?

Accepted Answer

A) The m/z value equals the molecular weight of the compound. 
B) The m/z value corresponds to a very stable carbanion. 
C) It has the largest peak height in the spectrum. 
D) It has the highest m/z value of all the peaks in the spectrum. 
E) The base peak is assigned a relative abundance equal to that of the parent ion. 
A) The m/z value equals the molecular weight of the compound. 
B) The m/z value corresponds to a very stable carbanion. 
C) It has the largest peak height in the spectrum. 
D) It has the highest m/z value of all the peaks in the spectrum. 
E) The base peak is assigned a relative abundance equal to that of the parent ion.

Question 17

Identify the compound that has a formula of C5H10 and bending vibrations at 990 and 910 cm-1.

Accepted Answer

A) 1-pentene 
B) cis-2-pentene 
C) trans-2-pentene 
D) 2-methyl-1-butene 
E) 2-methyl-2-butene 
A) 1-pentene 
B) cis-2-pentene 
C) trans-2-pentene 
D) 2-methyl-1-butene 
E) 2-methyl-2-butene

Question 18

Give the ion that corresponds to a m/z ratio of 56 in a mass spectrum of 1-butanol.

Accepted Answer

A)    
B)    
C)    
D)    
E) none of the above 
A)    
B)    
C)    
D)    
E) none of the above

Question 19

Which m/z peak is expected to be the base peak of cyclopentanol?

Accepted Answer

A) 57 
B) 43 
C) 29 
D) 85 
E) 86 
A) 57 
B) 43 
C) 29 
D) 85 
E) 86

Question 20

Give the ion that corresponds to a m/z ratio of 58 in a mass spectrum of 2-pentanone.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Exam 14: Mass Spectrometry, Infrared Spectroscopy, and Uvvis Spectroscopy

Which of the following functional groups typically exhibits a carbonyl stretch at the lowest frequency?

In the mass spectrum of 1,2-dichloroethane, what is the m/z of the molecular ion peak of greatest intensity?

At what wavenumber will the C-H stretch involving an sp carbon appear?

Deduce a possible structure for the compound with the IR absorptions below. C5H8O: 3000, 1750 cm-1

Which of the following carbonyl groups exhibits the highest wavenumber in infrared spectroscopy?

An infrared wavelength of 4.48μm is equivalent to a wavenumber of ________ cm-1.

Which of the following compounds exhibits the highest λmax in UV spectra?

Which has a lower characteristic stretching frequency, the C=O bond or the C-O bond? Explain briefly.

Which has the higher speed in a vacuum, ultraviolet or infrared light?

Identify the compound with the longest λmax in an UV spectrum.

Absorption of UV-visible energy by a molecule results in ________.

Which compound's C≡C IR band is weakest, 1-butyne, 2-pentyne, or 3-hexyne? Why?

Which of the following species has a characteristic absorption at 2200 cm-1 in its IR spectrum?

Identify the bond with the lowest wavenumber in the IR spectrum.

Describe the fate of a molecule from introduction to detection in a mass spectrometer.

Which of the following is true about the base peak in mass spectrometry?

Identify the compound that has a formula of C5H10 and bending vibrations at 990 and 910 cm-1.

Give the ion that corresponds to a m/z ratio of 56 in a mass spectrum of 1-butanol.

Which m/z peak is expected to be the base peak of cyclopentanol?

Give the ion that corresponds to a m/z ratio of 58 in a mass spectrum of 2-pentanone.

Remembering General Chemistry: Electronic Structure and Bonding

Acids and Bases: Central to Understanding Organic Chemistry

An Introduction to Organic Compounds

Isomers: the Arrangement of Atoms in Space

Alkenes Thermodynamics and Kinetics

Reactions of Alkenes

Reactions of Alkynes Introduction to Multistep Synthesis

Electron Delocalization, Resonance, and Aromaticity More About Molecular Orbital Theory

Substitution Reactions of Alkyl Halides

Elimination Reactions of Alkyl Halides Competition Between Substitution and Elimination

Reactions of Alcohols, Ethers, Epoxides, and Sulfur-Containing Compounds

Organometallic Compounds

Reactions of Alkanes, Radicals

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones

Reactions at the Alpha Carbon of Carbonyl Compounds

Reactions of Benzene and Substituted Benzenes

More About Amines Heterocylic Compounds

Carbohydrates

Amino Acids, Peptides, and Proteins

Catalysis

The Organic Mechanisms of the Coenzymes

The Chemistry of Metabolism

Nucleosides, Nucleotides, and Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters

Deduce a possible structure for the compound with the IR absorptions below. C₅H₈O: 3000, 1750 cm^-1

An infrared wavelength of 4.48μm is equivalent to a wavenumber of ________ cm^-1.

Which of the following compounds exhibits the highest λ_max in UV spectra?

Identify the compound with the longest λ_max in an UV spectrum.

Which of the following species has a characteristic absorption at 2200 cm^-1 in its IR spectrum?

Identify the compound that has a formula of C₅H₁₀ and bending vibrations at 990 and 910 cm^-1.