Chapter 13 book Flashcards
What can you tell from Mass spectrometry?
Measure molecular weight and determine molecular formula
Fragments
radicals and cations lower molecular weight than ion
What is the tallest peak called
base peak
What happens to the molecular weight of nitrogen is involved
molecular weight is odd
If the molecule ion is 72 what could the molecular formula be
C5H12, C4H8O, C3H4O2
If the molecule ion is 100 what could the molecular formula be
C8H4, C7H16, C6H12,O, C5H8O2
If a Cl is involved what happens to the molecular ion
3:1 ratio
If a Br is involved what happens to the molecular ion
1:1 ratio
Aldehyde and Ketone fragment pattern
alpha cleavage: break bond between carbonyl carbon and adjacent
Alcohol fragment pattern
alpha cleavage: break bond between alkyl group and C that bears OH or H2O elimination with 2 bond
Amine fragment pattern
alpha cleavage: break bond between alkyl group and c that bears amine forming a resonance structure
Infrared Spectroscopy
technique used infrared light to interact with compounds which causes bonds to bend and vibrate causing certain functional groups to be at certain absorptions
photons
particles of electromagnetic radiation which have quantum
quantum
discrete amount of energy
wavelength
distance from 1 point on wave to some point
frequency
of waves per unit of time
electromagnetic spectrum
electromagnetic radiation
wavenumber concerning wavelength and frequency
inversely proportional to wavelength and proportional to the frequency
What happens if frequencies match with a bond
they will be absorbed by bond
100% transmittance means that
none was absorbed
0% transmittance means that
all was absorbed
Where is the functional group region
> 1500
What do Stronger bonds do in IR
higher frequency needed so absorb high wavenumber
What do lighter atoms do in IR
higher frequency so absorb high wavenumber
What cause a molecule to absorb higher frequency for IR
Bond strength and atom mass
Bond type at 3600-3200 and is strong and broad
O-H
Bond type at 3500-3200 and is medium
N-H
Bond type at 3000-2850 and strong
Csp3-H
Bond type at 3150-3000 and medium
Csp2-H
Bond type at 3300 and medium
Csp-H
Bond type at 2250 and medium
C (Triple bond) C or C (triple bond) N
Bond type at 1800-1650 and strong
C=O
Bond type at 1650 and medium
C=C
Bond type at 1600 or 1500 and medium
Aromatic Ring
What happens as C-H bond strength increases
S character increases so higher wavenumber
Cl isotope mass number
35 and 37
Br isotope mass number
79 and 81
