Modern Analytical Techniques

Question 1

Fragmentation def

Answer 1

The process in mass spectrometry that causes a positive ions to split into pieces, one of which is a fragment ion, which will be registered at the detector

Question 2

Fragmentation process

Answer 2

Substance is bombarded with high energy electrons. The molecular ions produced is in a high energy state and excess energy causes the molecule to vibrate, weakening the bonds and causing the molecule to split into fragments

Question 3

What does the major peak show in a mass spectrometer?

Answer 3

The fragment ion

Question 4

In an exam, how would you analyse a mass spectrum of an organic molecule?

Answer 4

Draw the displayed formula. Work out the Mr and identify the molecular ion. Identify fragment ions which can be formed

Question 5

How does infrared spectroscopy work?

Answer 5

The frequency of infrared light corresponds to the natural frequency of vibrating covalent bonds. Molecules absorb this radiation, vibrate faster and therefore become warmer. The frequency of vibration absorbed when molecules bend or stretch is measured in an infrared spectrum

Question 6

What does the amount of vibration depend on?

Answer 6

The bond strength, the bond length, the mass of each atom involved in the bond

Question 7

Symmetric stretching def

Answer 7

When the bond length increases and decreases at the same time

Question 8

Asymmetric stretching def

Answer 8

When one bond length increases and the other decreases

Question 9

Bending def

Answer 9

When the bond angle increases or decreases