4.17 Spectroscopy ✓

positive ion formed when organic compound placed in mass spectrometer loses an electron

mass-to-charge ratio of molecukar ion which gives molecular mass of compound

clear peak at highest m/z value on right of mass spectrum

very small peak one unit after M+ peak

1.1% carbon present as carbon-13 isotope

process of molecular ions breaking down into smaller pieces known as fragments

fragment ions formed from breakdown of molecular ion

positively charged fragment ion + radical

no

yes

fragment ions found in spectrum may be different

bend or stretch more

movement along line between atoms

change in bond angle

-mass of atoms (heavier vibrate slower)
-strength of bond (stronger vibrate faster)

yes

scale proportional to frequency of wave

-ir radiation passes through atmosphere to earth where most is absorbed
-some is re-emitted in longer-wavelengths which is absorbed by greenhouse gases due to it matching their natural frequency
-this increases global temperatures

remote senors detect and measure vehicle emmisioms like CO, CO2 and hydrocarbons in an area

analyses ir absorbance in breath, ethanol bonds can be detected and the more the absorbance, the higher the reading and the more ethanol

1. elemental analysis: determine empirical formula using percentage composition
2. mass spectrometry: determine molecular mass and sections of a molecule
3. infrared spectroscopy: identify bonds and functional groups