NMR

Question 1

What has to be special about the solvent used?

Answer 1

Deuterated solvent (CDCl3 or CCl4)

Question 2

What is the principle of NMR?

Answer 2

1) Atoms with an odd mass number have nuclear spin
2) When placed in a magnetic field the atoms line with or against the field
3) Radio waves are passed through the sample which, with the magnetic field, creates resonance
4) Different nuclei require different amounts of energy to resonate
5) The energy can be detected and converted to a spectrum

Question 3

What is a reference standard (TMS)?

Answer 3

TMS which appears at 0ppm

Question 4

Why is TMS a suitable substance?

Answer 4

Volatile, Unreactive and none toxic

Question 5

What is integration?

Answer 5

The relative area of a peak in a proton NMR spectrum is related to the number of protons in that particular environment

Question 6

What is special about the height of each trace in proton NMR?

Answer 6

The height of each trace is proportional to the number of hydrogen atoms in ratio to other traces.

Question 7

What is peak splitting?

Answer 7

Provides information on the number of protons which are bonded to the adjacent carbon atoms

Question 8

What are the 3 types of chromatography?

Answer 8

1) Thin layer chromatography
2) Column chromatography
3) Gas chromatography

Question 9

How is the Rf value calculated?

Answer 9

Distance moved by component/Distance moved by solvent