spectrometry Flashcards
what is mass spectrometry used for
determine the molecular formula of a compound
how are molecular ions formed
when molecules in the sample ionised
what is electron impact ionisation
sample is vaporised and bombard with high energy electrons and electrons are removed
what can the molecular ion peak be used to determine
determine the relative molecular mass, molecular ions are able to break up into fragments during ionisation, this creates a fragmentation pattern on the mass spectrum, different compounds will produce different fragment peaks
how are particular bonds identified
by looking at the frequency they are absorbed at in an infrared spectrum
what is fingerprinting
it allows the identification of a molecule by comparison to the spectra
what does an infrared below 1500cm mean
it is largely unique to a specific molecule and allows identification of molecules
how can bonds present in greenhouse gases be impure
when they absorb infrared radiation that is reflected by the earth surface contributing to global warming, the infrared can. be used to identify impurities, extra peaks indicates impurities
what is optical isomerism
form of stereoisomerism and occurs as a result of chirality in molecules limited to molecules with a single chiral centre
what is an asymmetric carbon
chiral carbon and gives rise to optical isomers, these exist as non super imposable mirror images and differ in their effect on plane polarised light. One isomer rotates plane polarised light clockwise and the other rotates in anticlockwise
what is a racemic mixture
a mixture of equal amounts of enantiomers, that will have no overall effect on plane polarised light as the effects form 2 enantiomers will cancel out, racemic mixture are formed when 2 achiral molecule react
