Mass Spec can distinguish molecules that have the same nominal molecular weight,
ID: 967526 • Letter: M
Question
Mass Spec can distinguish molecules that have the same nominal molecular weight, but different exact masses e.g.CO2 and N2O.
1. True
Where does deutero-chloroform appear in a 13C NMR spectrum.
2. 78 ppm
If you have an odd number of nitrogen atoms in a molecule, you molecular weight will be odd.
3. true
If you have a molecule with a bromine atom, you should have an M+2 signal that is about 98% the height of the molecular ion.
4. True
If you have a weak IR signal at 2100-2300 cm-1, you could have a terminal alkyne or a cyano group.
5. true
One can recover samples from IR, NMR and Mass Spec.
6. false
For your determination of an unknown via spectroscopy, you will be given a proton NMR, a 13C NMR, an IR and a Mass Spec. Once you have determined your molecular weight from the Mass Spec, it is easiest to begin your elucidation by looking at the 13C first because;
7. all of the above
A fragment at 91 in the Mass Spec generally means you have a benzene ring with no alkyl substituents.
8. false
Explanation / Answer
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All answers are correct.