Question 1

Which type of spectroscopy (IR, UV, or MS) will best distinguish between the pair of compounds below? Give a brief reason.

Accepted Answer

The answer of Which type of spectroscopy (IR, UV, or...

Question 2

What region of the IR spectrum would be the most useful in distinguishing between the following two compounds?

Accepted Answer

A)  Above 2850 cm−1 
B)  Between 2850 and 2000 cm−1 
C)  Between 2000 and 1500 cm−1 
D)  Below 1500 cm−1

Question 3

Match each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur.
-C−C, C−O, C−N, and C−X single-bond vibrations.

Accepted Answer

A) 4000 to 2500 cm−1 
B) 2500 to 2000 cm−1 
C) 2000 to 1500 cm−1 
D) below 1500 cm−1

Question 4

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−1, but no significant peaks at 3000−3500 cm−1 or 1050−1250 cm−1?

Accepted Answer

A) 
 
B) 
 
C) 
 
D)

Question 5

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s).  (Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/)
-Refer to instructions. What peak represents the base peak?

Accepted Answer

The answer of Refer to the mass spectrum of 2-methylbutane...

Question 6

Arrange the following in order of increasing energy. A. 3842 nm B. 2870 cm−¹ C. 2.91 × 10¹⁶ Hz D. 1.99 × 10−¹⁸ J

Accepted Answer

The answer of Arrange the following in order of increasing...

Question 7

A 3.42 × 10−5 M solution of dibenzalacetone in ethanol produced an absorbance of 0.753 in a 1.00 cm cell. Based on this data, what is ε for this compound?

Accepted Answer

A)  2.57 × 105 
B)  2.20 × 104 
C)  4.54 × 10−5 
D)  2.92 × 104

Question 8

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?

Accepted Answer

A)  radio waves 
B)  ultraviolet 
C)  infrared 
D)  visible

Question 9

The amount of energy in electromagnetic radiation is related to the frequency and wavelength of the radiation. High energy radiation, like gamma rays, is of:

Accepted Answer

A)  low frequency and short wavelength 
B)  low frequency and long wavelength 
C)  high frequency and short wavelength 
D)  high frequency and long wavelength

Question 10

The amount of energy in infrared light corresponds to:

Accepted Answer

A)  the amount of energy needed to promote one electron from a bonding to an antibonding molecular orbital 
B)  the amount of energy needed to fragment a molecule 
C)  the amount of energy needed to strip a molecule of one electron to generate a cation radical 
D)  the amount of energy needed to increase certain molecular motions, such as bond vibrations, in organic molecules

Question 11

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−1 or 1600−1680 cm−1?

Accepted Answer

A) 
 
B) 
 
C) 
 
D)

Question 12

Which of the following bonds gives rise to a strong absorbance near 1700 cm−1 in the infrared spectrum?

Accepted Answer

A)  C=O 
B)  C−O 
C)  C=C 
D)  C−C

Question 13

What are the masses of the charged fragments produced by alpha cleavage of the following?

Accepted Answer

The answer of What are the masses of the charged...

Question 14

Circle any of the following compounds that would be a candidate to produce a UV absorption spectrum.

Accepted Answer

The answer of Circle any of the following compounds that...

Question 15

Which of the following does not involve the interaction of molecules with electromagnetic energy?

Accepted Answer

A)  mass spectrometry 
B)  infrared spectroscopy 
C)  ultraviolet spectroscopy 
D)  nuclear magnetic resonance spectroscopy

Question 16

Which of the following statements best describes the base peak in a mass spectrum?

Accepted Answer

A)  The peak from the most stable radical. 
B)  The peak from the species that has the isotope with the highest atomic number. 
C)  The peak of highest intensity. 
D)  The peak from the molecule minus an electron. 
E)  The M +1 peak

Question 17

Loratidine is the active ingredient in the antihistamine Claritin. Mass spectral analysis of loratidine shows M⁺ at m/z = 382. Loratidine is known to contain nitrogen. What is the minimum number of nitrogens in loratidine?

Accepted Answer

The answer of Loratidine is the active ingredient in the...

Question 18

What is the vertical axis of a mass spectrum?

Accepted Answer

A)  mass 
B)  energy 
C)  abundance 
D)  field strength

Question 19

The source of absorbance of light at a wavelength of 6600 nm would be:

Accepted Answer

A)  π → π* electron transitions 
B)  bond stretching 
C)  in-plane bending 
D)  out-of-plane bending 
E)  b, c, d

Question 20

Which of the following peaks is not prominent in the mass spectrum of 2-methylbutan-2-ol?

Accepted Answer

A)  M+ − 15 
B)  M+ − 18 
C)  M+ − 21 
D)  M+ − 29

Exam 10: Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

Which type of spectroscopy (IR, UV, or MS) will best distinguish between the pair of compounds below? Give a brief reason.

What region of the IR spectrum would be the most useful in distinguishing between the following two compounds?

Match each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. -C−C, C−O, C−N, and C−X single-bond vibrations.

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−¹, but no significant peaks at 3000−3500 cm−¹ or 1050−1250 cm−¹?

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s). (Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/) -Refer to instructions. What peak represents the base peak?

Arrange the following in order of increasing energy. A. 3842 nm B. 2870 cm−¹ C. 2.91 × 10¹⁶ Hz D. 1.99 × 10−¹⁸ J

A 3.42 × 10−⁵ M solution of dibenzalacetone in ethanol produced an absorbance of 0.753 in a 1.00 cm cell. Based on this data, what is ε for this compound?

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?

The amount of energy in electromagnetic radiation is related to the frequency and wavelength of the radiation. High energy radiation, like gamma rays, is of:

The amount of energy in infrared light corresponds to:

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−¹ or 1600−1680 cm−¹?

Which of the following bonds gives rise to a strong absorbance near 1700 cm−¹ in the infrared spectrum?

What are the masses of the charged fragments produced by alpha cleavage of the following?

Circle any of the following compounds that would be a candidate to produce a UV absorption spectrum.

Which of the following does not involve the interaction of molecules with electromagnetic energy?

Which of the following statements best describes the base peak in a mass spectrum?

Loratidine is the active ingredient in the antihistamine Claritin. Mass spectral analysis of loratidine shows M⁺ at m/z = 382. Loratidine is known to contain nitrogen. What is the minimum number of nitrogens in loratidine?

What is the vertical axis of a mass spectrum?

The source of absorbance of light at a wavelength of 6600 nm would be:

Which of the following peaks is not prominent in the mass spectrum of 2-methylbutan-2-ol?

Exam 10: Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

Which type of spectroscopy (IR, UV, or MS) will best distinguish between the pair of compounds below? Give a brief reason.

What region of the IR spectrum would be the most useful in distinguishing between the following two compounds?

Match each of the following groups of bond-types to the region of the infrared spectrum in which their absorptions occur. -C−C, C−O, C−N, and C−X single-bond vibrations.

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−1, but no significant peaks at 3000−3500 cm−1 or 1050−1250 cm−1?

Refer to the mass spectrum of 2-methylbutane shown below to answer the following question(s). (Spectrum obtained from: SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/) -Refer to instructions. What peak represents the base peak?

Arrange the following in order of increasing energy. A. 3842 nm B. 2870 cm−1 C. 2.91 × 1016 Hz D. 1.99 × 10−18 J

A 3.42 × 10−5 M solution of dibenzalacetone in ethanol produced an absorbance of 0.753 in a 1.00 cm cell. Based on this data, what is ε for this compound?

Which of the following regions in the electromagnetic spectrum corresponds to the radiation with the highest energy?

The amount of energy in electromagnetic radiation is related to the frequency and wavelength of the radiation. High energy radiation, like gamma rays, is of:

The amount of energy in infrared light corresponds to:

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−1 or 1600−1680 cm−1?

Which of the following bonds gives rise to a strong absorbance near 1700 cm−1 in the infrared spectrum?

What are the masses of the charged fragments produced by alpha cleavage of the following?

Circle any of the following compounds that would be a candidate to produce a UV absorption spectrum.

Which of the following does not involve the interaction of molecules with electromagnetic energy?

Which of the following statements best describes the base peak in a mass spectrum?

Loratidine is the active ingredient in the antihistamine Claritin. Mass spectral analysis of loratidine shows M+ at m/z = 382. Loratidine is known to contain nitrogen. What is the minimum number of nitrogens in loratidine?

What is the vertical axis of a mass spectrum?

The source of absorbance of light at a wavelength of 6600 nm would be:

Which of the following peaks is not prominent in the mass spectrum of 2-methylbutan-2-ol?

Which of the following compounds gives an infrared spectrum with a peak at ˜1750 cm−¹, but no significant peaks at 3000−3500 cm−¹ or 1050−1250 cm−¹?

Arrange the following in order of increasing energy. A. 3842 nm B. 2870 cm−¹ C. 2.91 × 10¹⁶ Hz D. 1.99 × 10−¹⁸ J

A 3.42 × 10−⁵ M solution of dibenzalacetone in ethanol produced an absorbance of 0.753 in a 1.00 cm cell. Based on this data, what is ε for this compound?

Which of the following compounds gives an infrared spectrum with no significant peaks at ˜3300 cm−¹ or 1600−1680 cm−¹?

Which of the following bonds gives rise to a strong absorbance near 1700 cm−¹ in the infrared spectrum?

Loratidine is the active ingredient in the antihistamine Claritin. Mass spectral analysis of loratidine shows M⁺ at m/z = 382. Loratidine is known to contain nitrogen. What is the minimum number of nitrogens in loratidine?