Mass Spectrometry And IR Spectroscopy Flashcards
What is mass spectrometry
An organic compound loses an electron to form a molecular ion
- occurs in a mass spectrometer
What does a mass spectrometer do
Detects the m/z ratio of the molecular ion, and produces a mass spectrum
What is m/z ratio
Mass to charge ratio
Gives the Mr of a compound
What is molecular ion, how is it represented
The positive ion formed when a molecule loses an electron, represented as M+
How to find Mr from mass spectrum
- identify M+ peak
- clearest peak furthest to the right
Why is there a smaller peak after the M+, what is it called
M+1 peak, one unit after M+ due to 1.1% Carbon existing as Carbon-13
What is fragmentation
Mass spectrometer breaks some M+ into smaller fragments (fragment ions) that cause other mass spectrum peaks
“Equation” for fragment ion
Molecular ion —> fragment ion + radical
Why don’t radicals show as peaks on the mass spectrum
Mass spectrometer only detects +ve ions
3 uses of mass spectrometry
- drug testing in sport
- MOT emissions testing
- monitoring air pollution
When can covalent bonds absorb IR radiation
When it is at the same frequency as their natural bond frequency
What does absorbing IR radiation do to covalent bonds
- bonds absorb energy causing increased vibration
Environment: where does IR radiation come from
Sun
How does IR radiation cause global warming
- earth reemits IR from sun at longer wavelength
- absorbed by greenhouse gases (its at their natural frequency)
- vibrating bonds reemit energy as radiation causing inc global temperatures
What has been done about global warming
Governments introducing policies promoting use of renewable energy resources
