ChemistsOnline*

 propanone  C3H6O

Proapanoic acid   C3H6O2

http://www.youtube.com/watch?v=_L4U6ImYSj0

Short video about  Mass Spectrometry

IR

·         Some molecules absorb energy from infrared radiation. This makes the bonds vibrate

·         Vibrations occur in one of 2 ways, a stretching vibration or a bending vibration

• Every bond vibrates at its own unique frequency depending on:

1. Bond strength

2. Bond length

3. Mass of atom at either end of the bond

·         Oxygen O₂ , and Nitrogen N₂ don’t absorb infrared radiation, but CO₂ , H₂O, nitric acid (NO) , and methane (CH₄) do absorb infrared radiation. They absorb IR because they change their polarity as they vibrate (due to the movement of dipoles in polar bonds)

·         Gases that do absorb IR radiation are called greenhouse gases – they stop some of the radiation emitted by the earth from escaping into space.