23:Spectroscopy

Question 1

How does infra-red spectroscopy work

Answer 1

Molecules can absorb infra-red radiation and energy absorbed causes the covalent bonds in the molecules to vibrate.

Question 2

What is fingerprinitng in spectroscopy

Answer 2

Comparing the compound’s vibrations with a spectral database to find an exact match

Question 3

What is a molecular ion

Answer 3

The ion formed when an intact molecule simply loses one electron

Question 4

What is the value of m/z for a molecular ion peak equal to

Answer 4

The Mr

Question 5

Where does the m+1 peak come from

Answer 5

A small percentage (1.1%) of earth’s carbon atoms are ¹³C rather than ¹²C this means if a molecule contains one of these heavier carbon atoms, the molecule will have a mass one greater than normal

Question 6

What is fragmentation

Answer 6

When larger molecules are bombarded with electrons (for mass spectrometry) parts can drop off, creating fragment ions

Question 7

What are the uses of mass spectrometry

Answer 7

Detection of compounds,

Estimating the amounts of specific substances,

Detect and measure relative amounts of specific isotope (used in carbon dating)