6.3.3 NMR Spectroscopy

Question 1

What is NMR?

Answer 1

An analytical technique used to work out the structure of an organic molecule.

Question 2

What is carbon-13 NMR?

Answer 2

Shows the number of carbon atoms that are in a molecule as well as the environment that they are in.

Question 3

What is proton NMR?

Answer 3

Shows the number of hydrogen atoms that are in a molecule as well as the environment that they are in.

Question 4

What does the atom’s environment depend on?

Answer 4

All the groups that it’s connected to.

Question 5

What is TMS?

Answer 5

Produces a single absorption peak in both types of NMR because all it’s carbon and hydrogen nuclei are in the same environment.

Question 6

Why is TMS chosen as a standard?

Answer 6

Because the absorption peak is at a lower frequency than anything else.

Question 7

Define chemical shift.

Answer 7

The difference in the radio frequency absorbed by the nuclei in the molecule being analysed and that absorbed by the same nuclei in the TMS.

Question 8

In carbon-13 NMR, what does the peaks on a spectra show?

Answer 8

The number of carbon environments in a molecule.

Question 9

In carbon-13 NMR, if there is a peak with the x axis value of 0, why do you not count it?

Answer 9

As this displays the reference peak from the TMS.