Question 1

Which compound's mass spectrum shows peaks at M, M+2, and M+4 whose abundances are in a ratio of 1:2:1?

Accepted Answer

A) cyclohexanol 
B) chlorocyclohexane 
C) 1,2-dichlorocyclohexane 
D) 1-bromopentane 
E) 1,5-dibromopentane 
A) cyclohexanol 
B) chlorocyclohexane 
C) 1,2-dichlorocyclohexane 
D) 1-bromopentane 
E) 1,5-dibromopentane E

Question 2

How could you distinguish the mass spectrum of 2,2-dimethylpropane from that of isopentane?

Accepted Answer

The loss of a methyl from 2,2-dimethylpropane forms a stable tertiary carbocation, while loss of a methyl from isopentane forms a less stable secondary carbocation. So the M-15 peak will be greater for 2,2-dimethylpropane.

Question 3

Which of the following is/are true about the MS of 1-bromobutane?

Accepted Answer

A) Peaks of approximately equal intensity are observed at m/z 136 and 138. 
B) The major fragmentation occurs by cleavage of the C-Br bond. 
C) The most intense peak occurs at m/z 43. 
D) both A and B 
E) both B and C 
A) Peaks of approximately equal intensity are observed at m/z 136 and 138. 
B) The major fragmentation occurs by cleavage of the C-Br bond. 
C) The most intense peak occurs at m/z 43. 
D) both A and B 
E) both B and C D

Question 4

Which of the following species has a characteristic absorption at 3300 cm-1 in its IR spectrum?

Accepted Answer

A) (CH3)2CHCCH 
B) (CH3)2CHN(CH3)2 
C) (CH3)2CHCCCH3 
D) (CH3)2CHCH=CH2 
E) (CH3)2CHCO2CH3 
A) (CH3)2CHCCH 
B) (CH3)2CHN(CH3)2 
C) (CH3)2CHCCCH3 
D) (CH3)2CHCH=CH2 
E) (CH3)2CHCO2CH3

Question 5

Which compound has the lowest carbonyl absorption frequency in an infrared spectrum?

Accepted Answer

A) ester 
B) ketone 
C) amide 
D) aldehyde 
E) carboxylic acid 
A) ester 
B) ketone 
C) amide 
D) aldehyde 
E) carboxylic acid

Question 6

Which of the following statements best explains the information we can gain from infrared spectroscopy?

Accepted Answer

A) It allows us to determine the number of protons in a compound. 
B) It allows us to determine the kinds of functional groups in a compound. 
C) It allows us to determine the molecular weight and the mass of some fragments of a compound. 
D) It allows us to determine the presence and nature of a carbocation in the compound. 
E) It allows us to determine the presence and nature of a free radical in the compound. 
A) It allows us to determine the number of protons in a compound. 
B) It allows us to determine the kinds of functional groups in a compound. 
C) It allows us to determine the molecular weight and the mass of some fragments of a compound. 
D) It allows us to determine the presence and nature of a carbocation in the compound. 
E) It allows us to determine the presence and nature of a free radical in the compound.

Question 7

Give the ion that corresponds to a m/z ratio of 43 in a mass spectrum of 2-pentanone.

Accepted Answer

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

Question 8

In the electromagnetic spectrum, ________ frequencies, ________ wavenumbers, and ________ wavelengths are associated with high energy.

Accepted Answer

A) high, small, long 
B) low, large, short 
C) low, small, short 
D) high, large, short 
E) high, small, short 
A) high, small, long 
B) low, large, short 
C) low, small, short 
D) high, large, short 
E) high, small, short

Question 9

Which of the following statements best explains the information we can gain from mass spectrometry?

Accepted Answer

A) It allows us to determine the number of protons in a compound. 
B) It allows us to determine the kinds of functional groups in a compound. 
C) It allows us to determine the molecular weight and the mass of some fragments of a compound. 
D) It allows us to determine the presence and nature of a carbocation in the compound. 
E) It allows us to determine the presence and nature of a free radical in the compound. 
A) It allows us to determine the number of protons in a compound. 
B) It allows us to determine the kinds of functional groups in a compound. 
C) It allows us to determine the molecular weight and the mass of some fragments of a compound. 
D) It allows us to determine the presence and nature of a carbocation in the compound. 
E) It allows us to determine the presence and nature of a free radical in the compound.

Question 10

Which of the following is the base peak for the compound below?

Accepted Answer

A) 77 
B) 92 
C) 15 
D) 57 
E) 43 
A) 77 
B) 92 
C) 15 
D) 57 
E) 43

Question 11

Which molecule below has a significant band in the IR at 2220 cm-1 (medium)?

Accepted Answer

A) CH3CH2CH2OH 
B) CH3C≡CCH2CH3 
C) CH3CH2CH(NH2)CH3 
D) (CH3)3N 
E) CH3CO2CH2CH3 
A) CH3CH2CH2OH 
B) CH3C≡CCH2CH3 
C) CH3CH2CH(NH2)CH3 
D) (CH3)3N 
E) CH3CO2CH2CH3

Question 12

Which of the following increases the absorbance of a solution of phenol in ethanol?

Accepted Answer

A) increasing the amount of phenol in the solution 
B) decreasing the amount of ethanol in the solution 
C) decreasing the light path through the solution 
D) both A and B 
E) both B and C 
A) increasing the amount of phenol in the solution 
B) decreasing the amount of ethanol in the solution 
C) decreasing the light path through the solution 
D) both A and B 
E) both B and C

Question 13

In which of the following molecules is the presence of the IR peak for C   C not observed?

Accepted Answer

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

Question 14

Give the fragment(s)that corresponds to a m/z charge of 58 for ethylpropylamine.

Accepted Answer

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

Question 15

Which of the following compounds has a vibration that is infrared inactive?

Accepted Answer

A) CH3-C   C-H 
B) H2O 
C)    
D) CO2 
E) CO 
A) CH3-C   C-H 
B) H2O 
C)    
D) CO2 
E) CO

Question 16

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 17

Which compound would be expected to show intense IR absorption at 1746 cm-1?

Accepted Answer

A) CH3CH2OCH2CH3 
B) CH3CO2CH3 
C) CH3CH2CCH 
D) CH3CH2SCH3 
A) CH3CH2OCH2CH3 
B) CH3CO2CH3 
C) CH3CH2CCH 
D) CH3CH2SCH3

Question 18

When a solution of an organic compound absorbs light whose wavelength is 400 nm, the solution appears ________.

Accepted Answer

A) yellow 
B) red 
C) purple 
D) blue 
E) white 
A) yellow 
B) red 
C) purple 
D) blue 
E) white

Question 19

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

Accepted Answer

Question 20

Which of the following compounds exhibits the pattern of m/z values shown below? 41, 43, 57, 87, 101, 116

Accepted Answer

A) propylbromide 
B) isopropyl bromide 
C) sec-butyl isopropyl ether 
D) 2-hexanol 
E) 2-butanone 
A) propylbromide 
B) isopropyl bromide 
C) sec-butyl isopropyl ether 
D) 2-hexanol 
E) 2-butanone

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

Which compound's mass spectrum shows peaks at M, M+2, and M+4 whose abundances are in a ratio of 1:2:1?

How could you distinguish the mass spectrum of 2,2-dimethylpropane from that of isopentane?

Which of the following is/are true about the MS of 1-bromobutane?

Which of the following species has a characteristic absorption at 3300 cm-1 in its IR spectrum?

Which compound has the lowest carbonyl absorption frequency in an infrared spectrum?

Which of the following statements best explains the information we can gain from infrared spectroscopy?

Give the ion that corresponds to a m/z ratio of 43 in a mass spectrum of 2-pentanone.

In the electromagnetic spectrum, ________ frequencies, ________ wavenumbers, and ________ wavelengths are associated with high energy.

Which of the following statements best explains the information we can gain from mass spectrometry?

Which of the following is the base peak for the compound below?

Which molecule below has a significant band in the IR at 2220 cm-1 (medium)?

Which of the following increases the absorbance of a solution of phenol in ethanol?

In which of the following molecules is the presence of the IR peak for C C not observed?

Give the fragment(s)that corresponds to a m/z charge of 58 for ethylpropylamine.

Which of the following compounds has a vibration that is infrared inactive?

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.

Which compound would be expected to show intense IR absorption at 1746 cm-1?

When a solution of an organic compound absorbs light whose wavelength is 400 nm, the solution appears ________.

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

Which of the following compounds exhibits the pattern of m/z values shown below? 41, 43, 57, 87, 101, 116

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

Which of the following species has a characteristic absorption at 3300 cm^-1 in its IR spectrum?

In the electromagnetic spectrum, frequencies, wavenumbers, and wavelengths are associated with high energy.

Which molecule below has a significant band in the IR at 2220 cm^-1 (medium)?

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.

Which compound would be expected to show intense IR absorption at 1746 cm^-1?

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