Question 1

Which molecule below has a significant band in the 1720 - 1780 cm-1 range of its IR spectrum?

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 2

Which compound would be expected to show intense IR absorption at 1715 cm-1?

Accepted Answer

A) CH3CH2CO2H 
B) 1-hexene 
C) 2-methylhexane 
D) CH3CH2CH2NH2 
A) CH3CH2CO2H 
B) 1-hexene 
C) 2-methylhexane 
D) CH3CH2CH2NH2

Question 3

Provide the structure of the two ions which result when the molecular ion of 2-methoxypentane undergoes fragmentation by

Accepted Answer

+ + CH₃CH₂CH₂CH @#IMG-DLM&_TB1830

Question 4

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 5

Is the λmax of phenol in aqueous solution affected by the pH of the solution? If so, explain how and why λmax changes.

Accepted Answer

As the pH of the solution increases, an

Question 6

Which of the following is not a common bending vibration of a CH2 group?

Accepted Answer

A) flip 
B) rock 
C) scissor 
D) twist 
E) wag 
A) flip 
B) rock 
C) scissor 
D) twist 
E) wag

Question 7

The mass spectra of alcohols often fail to exhibit detectable M peaks but instead show relatively large ________ peaks.

Accepted Answer

A) M+1 
B) M+2 
C) M-16 
D) M-17 
E) M-18 
A) M+1 
B) M+2 
C) M-16 
D) M-17 
E) M-18

Question 8

Which of the following statements is not true about electromagnetic radiation?

Accepted Answer

A) The velocity of light is directly proportional to the energy. 
B) All molecules absorb electromagnetic radiation at some frequency. 
C) Frequency is inversely proportional to wavelength. 
D) Energy is directly proportional to frequency. 
E) Energy is inversely proportional to wavelength. 
A) The velocity of light is directly proportional to the energy. 
B) All molecules absorb electromagnetic radiation at some frequency. 
C) Frequency is inversely proportional to wavelength. 
D) Energy is directly proportional to frequency. 
E) Energy is inversely proportional to wavelength.

Question 9

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 10

2-Methylhexane shows an intense peak in the mass spectrum at m/z = 43. Propose a likely structure for this fragment.

Accepted Answer

The answer of 2-Methylhexane shows an intense peak in the...

Question 11

Which molecule below has two significant bands in the IR at 2720 cm-1 and 2820 cm-1 (medium)?

Accepted Answer

A) CH3COCH2CH 
B) CH3CH2CO2CH3 
C) CH2=CHCH2CH3 
D) CH3CH2CH2CHO 
E) CH3CH2CH2OH 
A) CH3COCH2CH 
B) CH3CH2CO2CH3 
C) CH2=CHCH2CH3 
D) CH3CH2CH2CHO 
E) CH3CH2CH2OH

Question 12

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 13

How many centimeters (cm)are there in one micrometer (μm)?

Accepted Answer

A) 10-6 
B) 10-3 
C) 10-5 
D) 10-8 
E) 10-4 
A) 10-6 
B) 10-3 
C) 10-5 
D) 10-8 
E) 10-4

Question 14

Which of the following solvents is best used 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 15

Which of the following m/z values is the molecular ion for 2-butanone?

Accepted Answer

A) 15 
B) 29 
C) 43 
D) 57 
E) 72 
A) 15 
B) 29 
C) 43 
D) 57 
E) 72

Question 16

Ethyl acetate has the structure CH3CO2CH2CH3. Which set of m/z peaks is most consistent with this structure?

Accepted Answer

A) 88, 73, 43 
B) 88, 76, 45 
C) 88, 73, 45 
D) 88, 76, 43 
E) 88, 72, 70, 44 
A) 88, 73, 43 
B) 88, 76, 45 
C) 88, 73, 45 
D) 88, 76, 43 
E) 88, 72, 70, 44

Question 17

Identify the compound that has a formula of C3H6O with a stretching vibration at 1050 cm-1 and an absorption band at 3400 cm-1, but no doublet at 1380 cm-1.

Accepted Answer

A) 1-propanol 
B) 2-propanol 
C) ethyl methyl ether 
D) propen-1-ol 
E) propen-2-ol 
A) 1-propanol 
B) 2-propanol 
C) ethyl methyl ether 
D) propen-1-ol 
E) propen-2-ol

Question 18

Which molecule below has a significant band in the IR at 3300 cm-1 (medium and sharp)?

Accepted Answer

A) 1-pentene 
B) cyclohexane 
C) 2-heptyne 
D) 1-pentyne 
E) diethyl ether 
A) 1-pentene 
B) cyclohexane 
C) 2-heptyne 
D) 1-pentyne 
E) diethyl ether

Question 19

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

Accepted Answer

A) 63 
B) 76 
C) 78 
D) 80 
E) 82 
A) 63 
B) 76 
C) 78 
D) 80 
E) 82

Question 20

Which compound would be expected to show intense IR absorption at 2710 and 1705 cm-1?

Accepted Answer

A) CH3COCH2CH3 
B) PhCOCH3 
C) PhCHO 
D) CH2     CHCOCH3 
A) CH3COCH2CH3 
B) PhCOCH3 
C) PhCHO 
D) CH2     CHCOCH3

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

Which molecule below has a significant band in the 1720 - 1780 cm-1 range of its IR spectrum?

Which compound would be expected to show intense IR absorption at 1715 cm-1?

Provide the structure of the two ions which result when the molecular ion of 2-methoxypentane undergoes fragmentation by

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?

Is the λmax of phenol in aqueous solution affected by the pH of the solution? If so, explain how and why λmax changes.

Which of the following is not a common bending vibration of a CH2 group?

The mass spectra of alcohols often fail to exhibit detectable M peaks but instead show relatively large ________ peaks.

Which of the following statements is not true about electromagnetic radiation?

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

2-Methylhexane shows an intense peak in the mass spectrum at m/z = 43. Propose a likely structure for this fragment.

Which molecule below has two significant bands in the IR at 2720 cm-1 and 2820 cm-1 (medium)?

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

How many centimeters (cm)are there in one micrometer (μm)?

Which of the following solvents is best used in infrared spectroscopy?

Which of the following m/z values is the molecular ion for 2-butanone?

Ethyl acetate has the structure CH3CO2CH2CH3. Which set of m/z peaks is most consistent with this structure?

Identify the compound that has a formula of C3H6O with a stretching vibration at 1050 cm-1 and an absorption band at 3400 cm-1, but no doublet at 1380 cm-1.

Which molecule below has a significant band in the IR at 3300 cm-1 (medium and sharp)?

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

Which compound would be expected to show intense IR absorption at 2710 and 1705 cm-1?

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 a significant band in the 1720 - 1780 cm^-1 range of its IR spectrum?

Which compound would be expected to show intense IR absorption at 1715 cm^-1?

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?

Is the λ_max of phenol in aqueous solution affected by the pH of the solution? If so, explain how and why λ_max changes.

Which of the following is not a common bending vibration of a CH₂ group?

Which molecule below has two significant bands in the IR at 2720 cm^-1 and 2820 cm^-1(medium)?

Ethyl acetate has the structure CH₃CO₂CH₂CH₃. Which set of m/z peaks is most consistent with this structure?

Identify the compound that has a formula of C₃H₆O with a stretching vibration at 1050 cm^-1 and an absorption band at 3400 cm^-1, but no doublet at 1380 cm^-1.

Which molecule below has a significant band in the IR at 3300 cm^-1 (medium and sharp)?

Which compound would be expected to show intense IR absorption at 2710 and 1705 cm^-1?