MODULE 4: Spectoscropy

Question 1

What is mass spectrometry?

Answer 1

An analytical technique that is used to measure the mass-to-charge ratio of ions

Question 2

How do you deduce the molecular mass of a sample from a mass spectrometry reading?

Answer 2

Clearest peak at the highest value

Question 3

What is the M + 1 peak?

Answer 3

A peak after the M+ peak that occurs due to the carbon-13 isotope

Question 4

What is fragmentation?

Answer 4

When a sample is going through a mass spectrometer to become a cation, it may break down into smaller compounds called fragments

Question 5

What are the products of fragmentation?

Answer 5

Cations and radicals, but the mass spectrometer only detects cations

Question 6

What is infrared spectrometry?

Answer 6

Measuring how much radiation a bond can absorb before it breaks in organic compounds (between 200-4000 cm-1)

Question 7

What gases in the atmosphere re-emit infrared radiation and what effect does this have?

Answer 7

Water vapour, carbon dioxide and methane; global warming

Question 8

What absorbance will an alcohol have in infrared spectrometry?

Answer 8

Broad peak

Question 9

What absorbance will an aldehyde/ketone have in infrared spectrometry?

Answer 9

Sharp peak

Question 10

What absorbance will a carboxylic acid have in infrared spectrometry?

Answer 10

Very broad and sharp peak

Question 11

What are the uses of infrared spectrometry?

Answer 11

Identifying pollutant levels, carbon monoxide detection, breathalisers