Question 1

Which molecule below has two significant bands (medium and broad)in the 3300 - 3500 cm-1 range of its IR spectrum?

Accepted Answer

A) (CH3)3N 
B) CH3CH2NH2 
C) CH3CH2NH2 
D) CH3CON(CH3)2 
E) CH3OCH2CH2N(CH3)2 
A) (CH3)3N 
B) CH3CH2NH2 
C) CH3CH2NH2 
D) CH3CON(CH3)2 
E) CH3OCH2CH2N(CH3)2

Question 2

How can UV spectroscopy be used to estimate the nucleotide composition of DNA?

Accepted Answer

The melting temperature of DNA is the mi

Question 3

Which of the following carbon-hydrogen bonds exhibits the lowest wavenumber for a C-H stretch 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 4

How could IR spectroscopy be used to distinguish between the following pair of compounds?
CH3OCH2CH3 and CH3CH2CH2OH

Accepted Answer

O-H stretc

Question 5

Which molecule below has a significant band in the IR at 3400 cm-1 (strong and broad)?

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 6

Which of the following statements best explains how a hydrocarbon can show an M+2 peak in mass spectrometry?

Accepted Answer

A) from 13C and 1H 
B) from 12C and 2H 
C) from a single 13C 
D) from a single 3H 
E) from two 13C's 
A) from 13C and 1H 
B) from 12C and 2H 
C) from a single 13C 
D) from a single 3H 
E) from two 13C's

Question 7

Give the m/z ratio of the molecular ion in the mass spectrum of 1-butanol.

Accepted Answer

The answer of Give the m/z ratio of the molecular...

Question 8

Describe the molecular ion region in the mass spectrum of CH3CH2Br.

Accepted Answer

The natural abundance of the i

Question 9

Does the position of the stretch of the oxygen-hydrogen bond in alcohols depend on the concentration of the alcohol?

Accepted Answer

Yes, the more concentrated the alcohol,

Question 10

In the UV-visible spectrum of (E)-1,3,5-hexatriene, the lowest energy absorption corresponds to ________.

Accepted Answer

A) a π to π* transition 
B) a σ to π* transition 
C) a π to σ* transition 
D) a σ to σ* transition 
E) a σ to π transition 
A) a π to π* transition 
B) a σ to π* transition 
C) a π to σ* transition 
D) a σ to σ* transition 
E) a σ to π transition

Question 11

Which of the following is not true about the M+1 peak?

Accepted Answer

A) It is one m/z unit higher than the base peak. 
B) It is one m/z unit higher than the molecular ion peak. 
C) It is one m/z unit higher than the parent ion peak. 
D) It occurs because there is more than one naturally occurring isotope of carbon. 
E) This means that the number of carbon atoms in a compound can be calculated if the relative abundance of both the M and M+1 peaks is known. 
A) It is one m/z unit higher than the base peak. 
B) It is one m/z unit higher than the molecular ion peak. 
C) It is one m/z unit higher than the parent ion peak. 
D) It occurs because there is more than one naturally occurring isotope of carbon. 
E) This means that the number of carbon atoms in a compound can be calculated if the relative abundance of both the M and M+1 peaks is known.

Question 12

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 13

Which of the following characterizes the unusually intense peak of alkyl chlorides in MS spectrometry?

Accepted Answer

A) M + 1 peak 
B) M + 2 peak 
C) base peak 
D) parent peak 
E) none of the above 
A) M + 1 peak 
B) M + 2 peak 
C) base peak 
D) parent peak 
E) none of the above

Question 14

Give the m/z ratio that corresponds to the molecular ion in the mass spectrum of ethylpropylamine.

Accepted Answer

The answer of Give the m/z ratio that corresponds to...

Question 15

Which of the following statements is true about a molecular ion?

Accepted Answer

A) It is a compound that lost a pair of electrons. 
B) It is a compound that gained a pair of electrons. 
C) It is a compound that gained one electron. 
D) It is a compound that lost one electron. 
E) It is a compound that carries a free radical and a negative charge. 
A) It is a compound that lost a pair of electrons. 
B) It is a compound that gained a pair of electrons. 
C) It is a compound that gained one electron. 
D) It is a compound that lost one electron. 
E) It is a compound that carries a free radical and a negative charge.

Question 16

A compound shows a molecular ion peak at m/z 167. The relative intensities of the M and M+1 peaks are 50.0 and 4.4 respectively. How many carbons are in each molecule of the compound?

Accepted Answer

The answer of A compound shows a molecular ion peak...

Question 17

A mixture of two compounds give absorption bands at 1470, 1595, 1700, 2720, and 2740 cm-1. What compounds are present?

Accepted Answer

A) aldehyde + benzene 
B) ketone + benzene 
C) ester + benzene 
D) carboxylic acid + benzene 
E) anhydrice + benzene 
A) aldehyde + benzene 
B) ketone + benzene 
C) ester + benzene 
D) carboxylic acid + benzene 
E) anhydrice + benzene

Question 18

Which of the following compounds absorbs the longest wavelength of UV-visible light?

Accepted Answer

A) (
E) -2-butene 
B) (Z)-2-butene 
C) 1-hexene 
D) (Z)-1,3-hexadiene 
E) (
E) -1,3,5-hexatriene 
A) (
E) -2-butene 
B) (Z)-2-butene 
C) 1-hexene 
D) (Z)-1,3-hexadiene 
E) (
E) -1,3,5-hexatriene

Question 19

An increase in conjugation is correlated with ________ in the energy of the LUMO, ________ in the energy of the HOMO, and ________ in lmax.

Accepted Answer

A) a decrease, an increase, a decrease 
B) a decrease, an increase, an increase 
C) an increase, a decrease, a decrease 
D) an increase, a decrease, an increase 
E) an increase, an increase, a decrease 
A) a decrease, an increase, a decrease 
B) a decrease, an increase, an increase 
C) an increase, a decrease, a decrease 
D) an increase, a decrease, an increase 
E) an increase, an increase, a decrease

Question 20

Which of the following species has a characteristic broad absorption at 3200-3500 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

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

Which molecule below has two significant bands (medium and broad)in the 3300 - 3500 cm-1 range of its IR spectrum?

How can UV spectroscopy be used to estimate the nucleotide composition of DNA?

Which of the following carbon-hydrogen bonds exhibits the lowest wavenumber for a C-H stretch in infrared spectroscopy?

How could IR spectroscopy be used to distinguish between the following pair of compounds? CH3OCH2CH3 and CH3CH2CH2OH

Which molecule below has a significant band in the IR at 3400 cm-1 (strong and broad)?

Which of the following statements best explains how a hydrocarbon can show an M+2 peak in mass spectrometry?

Give the m/z ratio of the molecular ion in the mass spectrum of 1-butanol.

Describe the molecular ion region in the mass spectrum of CH3CH2Br.

Does the position of the stretch of the oxygen-hydrogen bond in alcohols depend on the concentration of the alcohol?

In the UV-visible spectrum of (E)-1,3,5-hexatriene, the lowest energy absorption corresponds to ________.

Which of the following is not true about the M+1 peak?

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

Which of the following characterizes the unusually intense peak of alkyl chlorides in MS spectrometry?

Give the m/z ratio that corresponds to the molecular ion in the mass spectrum of ethylpropylamine.

Which of the following statements is true about a molecular ion?

A compound shows a molecular ion peak at m/z 167. The relative intensities of the M and M+1 peaks are 50.0 and 4.4 respectively. How many carbons are in each molecule of the compound?

A mixture of two compounds give absorption bands at 1470, 1595, 1700, 2720, and 2740 cm-1. What compounds are present?

Which of the following compounds absorbs the longest wavelength of UV-visible light?

An increase in conjugation is correlated with ________ in the energy of the LUMO, ________ in the energy of the HOMO, and ________ in lmax.

Which of the following species has a characteristic broad absorption at 3200-3500 cm-1 in its IR spectrum?

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 molecule below has two significant bands (medium and broad)in the 3300 - 3500 cm^-1 range of its IR spectrum?

How could IR spectroscopy be used to distinguish between the following pair of compounds? CH₃OCH₂CH₃ and CH₃CH₂CH₂OH

Which molecule below has a significant band in the IR at 3400 cm^-1 (strong and broad)?

Describe the molecular ion region in the mass spectrum of CH₃CH₂Br.

A mixture of two compounds give absorption bands at 1470, 1595, 1700, 2720, and 2740 cm^-1. What compounds are present?

An increase in conjugation is correlated with in the energy of the LUMO, in the energy of the HOMO, and in l_max.

Which of the following species has a characteristic broad absorption at 3200-3500 cm^-1 in its IR spectrum?