AC12: Spectroscopic analysis Flashcards
When molecules absorb infrared radiation, what does the absorbed energy do the the bond
Make the covalent bonds in the molecule vibrate
Fragments in a mass spectrometer must carry a ________ charge
Positive
What does NMR stand for
Nuclear Magnetic Resonance
In proton NMR, what are the units of the chemical shift
ppm
In proton NMR, what is the area under the peak proportional to
The number of protons that contribute to it
When the NMR peaks split, what do the number of splits mean
How many protons are attached to the neighbouring carbons
If there were 2 protons on an adjacent carbon, how many peaks would there be in the NMR peak
3 peaks
What is the name for 2 peaks after splitting in an NMR spectrum
A doublet
If there’s 3 protons on adjacent carbon, how many peaks will there be after splitting
4 peaks
If the peak in the NMR splits into 3, what is this called
Triplet
If the peak in an NMR splits into 4, what is this called
Quartet
What is the equation/ rule for the number of peaks the peak splits into
n+1
In the n+1 rule, what does the n stand for
The number of protons on adjacent carbon
What are the 2 exceptions of the n+1 rule
- OH peaks are never split and the -OH protons don’t cause splitting of adjacent protons
- Equivalent protons don’t split each other
When doing a proton NMR, what must the solvent not contain
Hydrogen
