Analytical Techniques UNIT 1 and 2

Question 0

What are molecular ions

Answer 0

They are formed when molecules have electrons knocked off

Question 1

3 things that mass spectrometry can identify

Answer 1

Relative isotopic mass
Abundance of different isotopes
Relative molecular mass

Question 2

The molecular ion can be broken into….

Answer 2

Smaller fragments by the large number of electrons. The fragments that are ions show up on the mass spectrum, making a fragmentation pattern. This can be used to identify molecules and even their structure.

Question 3

Infrared spectroscopy helps you identify…..

Answer 3

Organic molecules

Question 4

What happens in infrared spectroscopy

Answer 4

A beam of IR radiation passed through sample of a chemical

The IR absorbed by covalent bonds in the molecule, increasing vibration energy

Bonds between different atoms absorb different frequencies of IR radiation. Bonds in different places absorb different frequencies to.

Question 5

The fingerprint region identifies a….

Answer 5

Molecule

The region between 1000 and 1550cm-1 on spectrum is called the fingerprint region. Unique to particular a compound, you can check this region of an unknown compounds IR spectrum against those of known compounds. If it matches up with one of them you know what the molecule is

Question 6

IR spectroscopy can also be used to find out….

Answer 6

How pure a compound is and identify any impurities. Impurities produce extra peaks in the fingerprint region

Question 7

Infrared energy absorption is linked to…

Answer 7

Global warming
Some of the electromagnetic radiation emitted by the sun is in the form infrared radiation. Molecules of greenhouse gases, like carbon dioxide, methane and water vapour, are really good at absorbing the infrared energy so if the amounts of them in the atmosphere increase it leads to global warming