C12: IR and Mass Spectroscopy

Question 1

Energy = ___ * ___ or (___* ___)/____

Answer 1

____ = hv (plancks constant * frequency)
or
____ = hc/lamda (plancks constant * speed of light)/wavelength

Question 2

IR is in _____

Answer 2

cm-1, 1/lamda(wavelength)

Question 3

absorption at a wavelength of 4um

Answer 3

(1/4um)*(10,000um/1cm) = 2500cm-1

Question 4

given a wavenumber of 2500cm-1 what is the wavelength

Answer 4

(1/2500cm)*(10,000um/cm) = 4um

Question 5

frequency _____ with an increase in atomic weight therefore C-H has a ______ frequency compared to ______

Answer 5

decreases, lower, C-D and C-C

Question 6

______ bonds are generally stiffer, thus require _______ frequency

Answer 6

strong bonds, higher

Question 7

C-C ____ C=C _____ C(triplebond)C frequency

Answer 7

> , >

Question 8

IR-active vibration is that the vibration must

______ the _____ of the molecule, cannot be _____

Answer 8

change, dipole moment, symmetrical

Question 9

isolated____conjugated_____aromatic frequency

Answer 9

> ,>

Question 10

sp ___ sp2 ____ sp3 frequency

Answer 10

> ,>

Question 11

resonance _______ frequency

Answer 11

decreases

Question 12

only _____ charged fragments are seen in mass spec

Answer 12

positively charged

Question 13

M+2 as large as M+ (mass spec)

Answer 13

Br is in the compound

Question 14

M+2 a third as large as M+ (mass spec)

Answer 14

Cl is in the compound

Question 15

I+ is recognized to appear at ______ with a ___ gap (mass spec)

Answer 15

127, large gap

Question 16

odd M+, some even fragments (mass spec)

Answer 16

N is in the compound

Question 17

M+2 larger than usual, 4% of M+ (mass spec)

Answer 17

S is in the compound

Question 18

strong M-18 peak

Answer 18

water from the dehydration of alcohol