additional info

Question 1

upper flammability limit

Answer 1

the highest concentration of a fuel as a percentage in air that will produce a flash of fire when an ignition source is present

Question 2

lower flammability limit

Answer 2

the lowest concentration of a fuel as a percentage in air that will produce a flash of fire when an ignition source is present

Question 3

TEA detection process

Answer 3

1. cleave nitro groups with pyrolysis and form radical
2. react radicals with ozone to get nitro group into excited state
3. decay back to ground state

Question 4

extracting vapours from volatile samples

Answer 4

use static head space sampling - sealed container
use dynamic headspace sampling - solid phase trap

Question 5

SPE methods and their affinities

Answer 5

normal phase - adsorbs polar
reverse phase - adsorbs non polar
size exclusion - adsorbs low MW molecules

Question 6

ion mobility spectrometry

Answer 6

1. molecules ionised by electric field
2. ions fired through tube against the action of the drift gas

faster than GC or LC
often paired with a mass spectrometer

Question 7

factors that affect ion mobility

Answer 7

• reduced mass of ion
• volume of drift gas
• probability of collision with drift gas
• charge on the ion