3.3.15 - NMR Spectroscopy

Question 1

NMR spectroscopy

Answer 1

An analytical technique that allows the structure of a molecule to be determined by analysing the energy of each bond energy

Question 2

Different peaks on a spectra print out

Answer 2

Different bond environments within a molecule absorb different amounts of energy meaning they show as different peaks on a spectra print out

Question 3

Bond environment peaks are measured against a standard molecule

Answer 3

Tetramethylsilane

Question 4

Tetramethylsilane

Answer 4

Contains 4 identical carbon and hydrogen environments and is seen as a peak at 0 ppm on the x-axis

Question 5

C13 NMR

Answer 5

Analyses the different carbon environments in a molecule

Question 6

Carbon environments that are near to an oxygen

Answer 6

Shifted to the right because oxygen is very electronegative and changes the bond environment and how it absorbs energy

Question 7

Molecules that have symmetry may display…

Answer 7

Fewer peaks than the number of carbon atoms in the molecule

Question 8

H1 NMR

Answer 8

Different hydrogen environments in a molecule are analysed and displayed as peaks on a spectra

Question 9

Samples being analysed in H1 NMR must be…

Answer 9

Dissolved in a non-hydrogen-containing solvent so it doesn’t produce and carbon peaks

Question 10

Common solvents for H1 NMR

Answer 10

CCl4
Deuterated solvents containing deuterium

Question 11

Singlet

Answer 11

No H on adjacent carbon

Question 12

No H on adjacent carbon

Answer 12

Singlet

Question 13

Doublet

Answer 13

1 H on adjacent carbon

Question 14

1 H on adjacent carbon

Answer 14

Doublet

Question 15

Triplet

Answer 15

2 H on adjacent carbon

Question 16

2 H on adjacent carbon

Answer 16

Triplet

Question 17

Quartet

Answer 17

3 H on adjacent carbon

Question 18

3 H on adjacent carbon

Answer 18

Quartet