ch 15 Flashcards
Which of the following is not true about electromagnetic radiation?
A) frequency is directly proportional to wavelength
B) frequency is directly proportional to energy
C) frequency is inversely proportional to wavelength
D) wavelength is inversely proportional to energy
E) none of these
A) frequency is directly proportional to wavelength
Which of the following electromagnetic radiation has the highest energy?
A) UV
B) X-ray
C) IR
D) microwave
E) visible
B) x ray
Which of the following electromagnetic radiation has the longest wavelength?
A) UV
B) X-ray
C) IR
D) microwave
E) visible
D) microwave
Which of the following electromagnetic radiation has the highest frequency?
A) UV
B) X-ray
C) IR
D) microwave
E) visible
B) x ray
Arrange the following electromagnetic radiation in decreasing (highest to lowest) order of frequency.
A) V>III>IV>II>I
B) II>V>III>IV>I
C) I>IV>III>V>II
D) V>II>IV>III>I
E) II>IV>V>III>I
B) II>V>III>IV>I
Arrange the following electromagnetic radiation in decreasing (highest to lowest) order of wavelength.
A) V>III>IV>II>I
B) II>V>III>IV>I
C) I>IV>III>V>II
D) V>II>IV>III>I
E) II>IV>V>III>I
E) II>IV>V>III>I
- Which of the following information is primarily obtained from infrared spectroscopy?
A) arrangement of carbon and hydrogen atoms in a compound
B) molecular weight of a compound
C) conjugated system present in a compound
D) functional groups present in a compound
E) all of these
D) functional groups present in a compound
Absorption of _______radiation results in vibrational excitation of the bonds in a compound.
A) UV
B) Microwave
C) IR
D) Visible
E) x-ray
C) IR
Which of the following vibrations are observed in IR spectroscopy?
A) stetching
B) rotational
C) bending
D) A & B
E) A & C
A and C
stretching and bending
Which of the following is currently most often used to indicate the location of a signal on an IR spectrum?
A) wavelength
B) wavenumber
C) frequency
D) A & B
E) all of these
B) wavenumber
Which of the following are units for wavenumber in IR spectroscopy?
A) cm -1
B) cm
C) J.s -1
D) mm
E) none of these
A) cm -1
Which of the following wavenumber corresponds to the functional group region on an
IR spectrum?
A) 1500-4000cm -1
B) 400-4000cm -1
C) 400-1500cm -1
D) 1500-2500cm -1
E) none of these
A) 1500-4000cm -1
Which of the following wavenumber corresponds to the fingerprint region on an IR
spectrum?
A) 1500-4000cm -1
B) 400-4000cm -1
C) 400-1500cm -1
D) 1500-2500cm -1
E) none of these
C) 400-1500cm -1
Which of the following statement(s) is(are) true about the frequency of a stretching vibration according to Hooke’s law?
A) it is directly proportional to strength of the bond & the reduced mass
B) it is inversely proportional to strength of the bond & the reduced mass
C) it is directly proportional to strength of the bond
D) it is inversely proportional to the reduced mass
E) C & D
E) C & D
Rank absorption of the indicated bonds in decreasing (highest to lowest) order of wavenumber.
A) III>II>I
B) I>II>III
C) II>I>III
D) III>I>II
E) none of these
B) I>II>III
Which one of the following compounds will have the lowest wavenumber for carbonyl absorption?
A) I
B) II
C) III
D) IV
E) none of these
D) IV
Which one of the following compounds will have the highest wavenumber for C=C absorption?
A) I
B) II
C) III
D) IV
E) V
C) III
Which of the following compounds will have the highest wavenumber for carbonyl absorption?
A) I
B) II
C) III
D) II & III
C) III
Rank absorption of the indicated bonds in decreasing (highest to lowest) order of wavenumber.
A) I>V>II>IV>III
B) IV>II>I>V>III
C) II>I>V>III>IV
D) IV>I>V>II>III
E) IV>II>V>I>III
E) IV>II>V>I>III
Which of the following statement(s) is(are) true for an IR-active bond?
A) the bond must be symmetrical
B) a vibration must result in a change of bond length
C) a vibration must result in a change of bond angle
D) a vibration must result in a change of bond dipole
E) all of these
D) a vibration must result in a change of bond dipole
Which of the following bonds is IR-inactive?
A) I
B) II
C) III
D) I & IV
E) I & III
E) I & III
Which of the following bonds has the weakest absorption?
A) C=C
B) O—H
C) C=O
D) sp 3 C—H
E) A & D
A) C=C
Which of the following bonds has the strongest absorption?
A) C=N
B) CC
C) C=O
D) sp 2 C—H
E) C—O
C) C=O
3-Hexyne does not show absorption in the range of 2000-2200 cm —1 , whereas 1-hexyne does. Which of the following explains the reason for this absence of absorption for 3-hexyne?
A) it is a symmetrical compound
B) there is no change in bond dipole
C) there is no bond dipole
D) it is an unsymmetrical compound
E) A, B & C
E) A, B & C
Which of the following alkene groups will produce the strongest signal?
A) I
B) II
C) III
D) IV
A) I
Diluted alcohols show a _____absorption around 3600cm -1 , due to _____.
A) sharp, hydrogen bonding
B) broad, hydrogen bonding
C) sharp, absence of hydrogen bonding
D) broad, absence of hydrogen bonding
C) sharp, absence of hydrogen bonding
Concentrated alcohols show a _____absorption in the region of 3200-3600cm -1 , due to
_____.
A) sharp, hydrogen bonding
B) broad, hydrogen bonding
C) sharp, polarity
D) broad, polarity
B) broad, hydrogen bonding
Carboxylic acids show a very broad absorption for the OH compared to alcohols, because they can form a ______.
A) dimer
B) polymer
C) trimer
D) tetramer
A) dimer
Primary amines show two medium absorption bands around 3400 cm -1 , due to _______.
A) symmetric stretching
B) asymmetric stretching
C) both symmetric and asymmetric stretching
D) hydrogen bonding
C) both symmetric and asymmetric stretching
Which of the following compounds will show a broad absorption around 3300 cm -1 and a sharp absorption at 1650 cm -1 ?
A) I
B) II
C) III
D) IV
E) V
D) IV
