Question 1

The mass spectrum of an unknown compound has a molecular ion peak with a relative abundance of 43.27% and an M + 1 peak with a relative abundance of 3.81%.How many carbon atoms are in the compound?

Accepted Answer

The answer of The mass spectrum of an unknown compound...

Question 2

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.

Question 3

Which of the following wavenumbers corresponds to the bond shown below? C  C

Accepted Answer

A) 1650 cm-1 
B) 2100 cm-1 
C) 1100 cm-1 
D) 3300 cm-1 
E) 2850 cm-1

Question 4

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

Question 5

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

Question 6

Identify the compound with the longest λmax in an UV spectrum.

Accepted Answer

A) benzene 
B) phenol 
C) phenolate ion 
D) aniline 
E) anilinium ion

Question 7

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

Accepted Answer

The answer of Does the position of the stretch of...

Question 8

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

Question 9

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

Question 10

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.

Question 11

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

Question 12

Which of the following m/z values correspond to the M+2 peak of the following compound?

Accepted Answer

A) 149 
B) 150 
C) 151 
D) 152 
E) 153

Question 13

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.

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 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.

Question 16

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)

Question 17

Which of the following methods is most suitable for studying conjugation in molecules?

Accepted Answer

A) infrared 
B) NMR 
C) mass spectrometry 
D) X-ray 
E) UV visible

Question 18

Ultraviolet spectroscopy provides information about

Accepted Answer

A) functional groups. 
B) single bonds. 
C) isolated double bonds. 
D) conjugated double bonds. 
E) none of the above.

Question 19

Which m/z peak is expected to be the base peak of cyclopentanol?

Accepted Answer

A) 57 
B) 43 
C) 29 
D) 85 
E) 86

Question 20

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

Accepted Answer

The answer of How would you use mass spectrometry to...

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

The mass spectrum of an unknown compound has a molecular ion peak with a relative abundance of 43.27% and an M + 1 peak with a relative abundance of 3.81%.How many carbon atoms are in the compound?

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

Which of the following wavenumbers corresponds to the bond shown below? C C

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

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.

Identify the compound with the longest λ_max in an UV spectrum.

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

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

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 infrared spectroscopy?

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

Which of the following m/z values correspond to the M+2 peak of the following compound?

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

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

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

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

Which of the following methods is most suitable for studying conjugation in molecules?

Ultraviolet spectroscopy provides information about

Which m/z peak is expected to be the base peak of cyclopentanol?

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

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

The mass spectrum of an unknown compound has a molecular ion peak with a relative abundance of 43.27% and an M + 1 peak with a relative abundance of 3.81%.How many carbon atoms are in the compound?

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

Which of the following wavenumbers corresponds to the bond shown below? C C

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

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.

Identify the compound with the longest λmax in an UV spectrum.

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

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

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 infrared spectroscopy?

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

Which of the following m/z values correspond to the M+2 peak of the following compound?

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

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

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

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

Which of the following methods is most suitable for studying conjugation in molecules?

Ultraviolet spectroscopy provides information about

Which m/z peak is expected to be the base peak of cyclopentanol?

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

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.

Identify the compound with the longest λ_max in an UV 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 3400 cm^-1 (strong and broad) ?