6.3.2 Spectroscopy

Question 1

What is the standard chemical in carbon and hydrogen NMR? Where does this show on a spectra?

Answer 1

TMS; peak at 0

Question 2

What does an NMR machine detect?

Answer 2

The energy absorbed by a pair of spinning nuclei to go to a higher level

Question 3

In NMR, what does electron shielding do to the chemical shift and how can be decreased?

Answer 3

Decreases chemical shift;

Being close to an atom(s) of high electronegativity (0) or high electron density (C=C)

Question 4

In C-13 NMR it tells us how how ___ _ _____ there are in a sample by the ___ in the spectra and therefore the types of carbon present (___ ___)

Answer 4

Carbon environments;
peaks;
chemical shift;

Question 5

Process to interpret a C-13 NMR:

Answer 5

1. Write down possible isomers
2. Identify carbon environments- rule out ones that don’t match peaks
3. Data sheet

Question 6

What is a carbon environment?

Answer 6

The atoms or groups of atoms near a carbon- the full molecule not just immediate atoms

Question 7

When identifying carbon environments in cyclic compounds, what do you look for?

Answer 7

Symmetry