Question 1

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

Accepted Answer

Question 2

Which of the following molecular changes is necessary for mass spectrometry to occur?

Accepted Answer

A) excitation of an electron from the ground state to higher energy state 
B) change of alignment of an electron in a magnetic field 
C) change of alignment of a proton in a magnetic field 
D) loss of an electron 
E) molecular vibration 
A) excitation of an electron from the ground state to higher energy state 
B) change of alignment of an electron in a magnetic field 
C) change of alignment of a proton in a magnetic field 
D) loss of an electron 
E) molecular vibration

Question 3

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 4

Identify the compound that has a formula of C4H9N and has one absorption band at 3400 cm-1 and a doublet at 1380 cm-1.

Accepted Answer

A) diethylamine 
B) methylpropylamine 
C) isopropylmethylamine 
D) butylamine 
E) dimethylethylamine 
A) diethylamine 
B) methylpropylamine 
C) isopropylmethylamine 
D) butylamine 
E) dimethylethylamine

Question 5

Describe the similarities and differences in the infrared spectra of methyl propanoate and butanoic acid.

Accepted Answer

Both compounds give an infrare

Question 6

In electron ionization,a sample is bombarded with a beam of high energy

Accepted Answer

A) protons. 
B) neutrons. 
C) electrons. 
D) positrons. 
E) ions. 
A) protons. 
B) neutrons. 
C) electrons. 
D) positrons. 
E) ions.

Question 7

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)

Question 8

Predict the molecular formula of the compound represented below based on the MS data given.

Accepted Answer

A) C6H12 
B) C5H24 
C) C4H6O2 
D) C3H8O2 
E) C5H8O 
A) C6H12 
B) C5H24 
C) C4H6O2 
D) C3H8O2 
E) C5H8O

Question 9

Which color is observed when a sample absorbs light at 650 nm?

Accepted Answer

A) yellow 
B) orange 
C) red 
D) violet 
E) greenish-blue 
A) yellow 
B) orange 
C) red 
D) violet 
E) greenish-blue

Question 10

Which compound's carbonyl stretch occurs at the lowest wavenumber?

Accepted Answer

A) CH3CH2CH2CHO 
B) CH3COCH2CH3 
C) CH3CH2CONH2 
D) CH3CH2CO2CH3 
E) CH3CH2COCH2CH3 
A) CH3CH2CH2CHO 
B) CH3COCH2CH3 
C) CH3CH2CONH2 
D) CH3CH2CO2CH3 
E) CH3CH2COCH2CH3

Question 11

Deduce a possible structure for the compound with the IR absorptions below.
C3H3Br: 3300,2900,2100 cm-1

Accepted Answer

Question 12

Ethyne (HCCH)does not show IR absorption in the region 2000-2500 cm-1 because

Accepted Answer

A) C-H stretches occur at lower energies. 
B) CC stretches occur at about 1640 cm-1. 
C) there is no change in the dipole moment when the CC bond in ethyne stretches. 
D) there is a change in the dipole moment when the CC bond in ethyne stretches. 
A) C-H stretches occur at lower energies. 
B) CC stretches occur at about 1640 cm-1. 
C) there is no change in the dipole moment when the CC bond in ethyne stretches. 
D) there is a change in the dipole moment when the CC bond in ethyne stretches.

Question 13

In the mass spectrum of bromoform,CHBr3,molecular ion peaks appear at m/z 250,251,252,and 253? What is the ratio of the intensities of these peaks?

Accepted Answer

A) 1:1:1:1 
B) 1:2:2:1 
C) 1:3:3:1 
D) 2:3:3:2 
E) 3:2:2:3 
A) 1:1:1:1 
B) 1:2:2:1 
C) 1:3:3:1 
D) 2:3:3:2 
E) 3:2:2:3

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

Give the ion that corresponds to a m/z ratio of 43 in a mass spectrum of 2-pentanone.You may choose more than one answer.

Accepted Answer

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

Question 16

Provide the structure of the species which results when the molecular ion of 4-heptanone undergoes fragmentation via a McLafferty rearrangement.

Accepted Answer

The answer of Provide the structure of the species which...

Question 17

Which of the following species has a characteristic absorption at 1250 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 18

Is it possible to have an M + 2 peak in mass spectrometry? Explain.

Accepted Answer

A mass spectrum can show an M + 2 peak f

Question 19

How would you use mass spectrometry to quickly distinguish between the two compounds below that have the same molecular mass?

Accepted Answer

The M+2 in the brominated comp

Question 20

Which of the following m/z values correspond to the molecular ion peak of the following compound?

Accepted Answer

A) 124 
B) 125 
C) 135 
D) 136 
E) 137 
A) 124 
B) 125 
C) 135 
D) 136 
E) 137

Exam 13: Mass Spectrometry,infrared Spectroscopy,and Uvvis Spectroscopy

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

Which of the following molecular changes is necessary for mass spectrometry to occur?

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

Identify the compound that has a formula of C4H9N and has one absorption band at 3400 cm-1 and a doublet at 1380 cm-1.

Describe the similarities and differences in the infrared spectra of methyl propanoate and butanoic acid.

In electron ionization,a sample is bombarded with a beam of high energy

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

Predict the molecular formula of the compound represented below based on the MS data given.

Which color is observed when a sample absorbs light at 650 nm?

Which compound's carbonyl stretch occurs at the lowest wavenumber?

Deduce a possible structure for the compound with the IR absorptions below. C3H3Br: 3300,2900,2100 cm-1

Ethyne (HCCH)does not show IR absorption in the region 2000-2500 cm-1 because

In the mass spectrum of bromoform,CHBr3,molecular ion peaks appear at m/z 250,251,252,and 253? What is the ratio of the intensities of these peaks?

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

Give the ion that corresponds to a m/z ratio of 43 in a mass spectrum of 2-pentanone.You may choose more than one answer.

Provide the structure of the species which results when the molecular ion of 4-heptanone undergoes fragmentation via a McLafferty rearrangement.

Which of the following species has a characteristic absorption at 1250 cm-1 in its IR spectrum?

Is it possible to have an M + 2 peak in mass spectrometry? Explain.

How would you use mass spectrometry to quickly distinguish between the two compounds below that have the same molecular mass?

Which of the following m/z values correspond to the molecular ion peak of the following compound?

Remembering General Chemistry: Electronic Structure and Bonding

Acids and Bases: Central to Understanding Organic Chemistry

An Introduction to Organic Compounds: Nomenclature, physical Properties, and Structure

Isomers: the Arrangement of Atoms in Space

Alkenes: Structure,nomenclature,and an Introduction to Reactivity - Thermodynamics and Kinetics

The Reactions of Alkenes - the Stereochemistry of Addition Reactions

The Reactions of Alkynes - Introduction to Multistep Synthesis

Delocalized Electrons: Their Effect on Stability, pka, and the Products of a Reaction - Aromaticity and Electronic Effects: an Introduction to the Reactions of Benzene

Substitution and Elimination Reactions of Alkyl Halides

Reactions of Alcohols, ethers, epoxides, amines and Sulfur-Containing Compounds

Organometallic Compounds

Radicals

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones

Reactions at the Α-Carbon

Reactions of Benzene and Substituted Benzenes

More About Amines - Reactions of Heterocylic Compounds

The Organic Chemistry of Carbohydrates

Amino Acids,peptides,and Proteins

Catalysis in Organic Reactions and in Enzymatic Reactions

The Organic Chemistry of the Coenzymes, compounds Derived From Vitamins

The Organic Chemistry of the Metabolic Pathways

The Organic Chemistry of Lipids

The Chemistry of the Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters

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

Identify the compound that has a formula of C₄H₉N and has one absorption band at 3400 cm^-1 and a doublet at 1380 cm^-1.

Deduce a possible structure for the compound with the IR absorptions below. C₃H₃Br: 3300,2900,2100 cm^-1

Ethyne (HCCH)does not show IR absorption in the region 2000-2500 cm^-1 because

In the mass spectrum of bromoform,CHBr₃,molecular ion peaks appear at m/z 250,251,252,and 253? What is the ratio of the intensities of these peaks?

Which of the following species has a characteristic absorption at 1250 cm^-1 in its IR spectrum?