7/27/2019 Assignment (IR and Mass Spec)

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2211 Concept Check ch 12 Name___________________________________

Print Last N ame, First Nam e

Period __________________Date_____________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1) At what m/z would the base peak of (E)- 2- hexene occur? 1)

A) 84

B) 69

C) 55D) 41

E) 28

2) Which of the following most closely matches the CC stretching frequency? 2)

A) 1200

B) 2200

C) 1700

D) 3000

E) 3300

3) When a high energy electron impacts molecule M in the ionization chamber, what type of species

is initially produced?

3)

A) radical cation

B) cation

C) radical

D) radical anion

E) anion

4) Which compound would be expected to show intense IR absorption at 1640 cm - 1? 4)

A) 2-methylheptane

B) CH3CH2COCH3

C) CH3CH2CH2OH

D) hex- 1- ene

5) In addition to a carbonyl stretch, which of the following molecules exhibits two characteristic

stretches at 2700 and 2800 cm- 1?

5)

A) CH3CH2CH2COCl

B) CH3CH2CH2CHO

C) CH3CH2CH2CO2H

D) (CH3CH2)2CO

E) CH3CH2CO2CH3

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7/27/2019 Assignment (IR and Mass Spec)

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6) What are the predicted m/z values (masses )and relative heights of all the molecular ions of

1- bromoethane that would appear on a mass spectrum?

6)

A) M+peak at m/z =79 and an M+1 peak at 81

The M+1 peak is approximately 1/2 the height of the M+peak.

B) M+peak at m/z =108 and an M+1 peak at m/z =110

The M+1 peak is approximately 1/2 the height of the M+peak.

C) M+peak at m/z =79 and an M+1 peak at 81

The M+1 peak is approximately the same height as the M+peak.

D) M+peak at m/z =108 and an M+2 peak at m/z =110M+2 peak is approximately 1/2 the height of the M+peak.

E) M+peak at m/z =108 and an M+2 peak at m/z =110

The M+2 peak is approximately the same height as the M+peak.

7) Which of the following does not have a broad absorption with one or more spikes that is centered

about 3300 cm- 1 in the IR?

7)

A) (CH3)3CNH2

B) (CH3CH2CH2)2NH

C) (CH2=CHCH2)2NH

D) (CH3CH2CH2)3N

E) CH3CH2CH2NH2

8) Which sequence ranks the regions of the electromagnetic spectrum in order of increasing energy?

1) infrared 2) ultraviolet 3) radio wave

8)

A) 3 <2 <1

B) 1 <3 <2

C) 2 <1 <3

D) 3 <1 <2

9) The frequency of the stretching vibration of a bond in IR spectroscopy depends on what two

quantities?

9)

A) the electronegativity of the atoms and the nuclear charges of the atoms

B) the masses of the atoms and the stiffness of the bond

C) the stiffness of the bond and the electronegativity of the atoms

D) the electronegativity of the atoms and the masses of the atoms

E) the nuclear charges of the atoms and the atomic radii

10) The mass spectrum of which compound has M+and M+2 peaks of approximately equal intensity? 10)

A) 3-pentanol

B) 3- iodopentane

C) pentane

D) 3- bromopentane

E) 3- chloropentane

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