Analytical Techniques Flashcards
What does absorption of infrared radiation cause?
Covalent bonds to vibrate and become hotter
What is the greenhouse effect?
Certain gases absorb some of the infrared radiation from the sun and maintains the Earth at a steady temperature.
What are the greenhouse gases in order of abundance and which is the strongest absorber of infrared radiation?
Water vapour (weakest)
Carbon dioxide
Methane (strongest)
What causes global warming?
The C=O O-H C-H in carbon dioxide water and methane absorb infrared energy causing vibrations which emit energy in the form of radiation contributing to global warming.
What is global warming causing?
Heavy rainfall Melting sea ice Drought Rising sea levels Extreme storms and hurricanes
Which ways can covalent bonds vibrate?
Stretches
Bends
Why can IR absorptions indicate which type of covalent bond it is?
Each different type of bond absorb IR of different energy so it helps identify why type of molecule it is
What are the axis of an IR spectrum and the units!
Y axis- transmittance (%)
X axis- DECREASING wave number (cm-1) and energy
Where is the fingerprint region of an IR spectrum and what is it?
Below 1500 cm-1
The unique pattern for that molecule
What are some infrared spectrometers used for?
Breathalysers- testing for alcohol
Monitoring air pollution
What does spectroscopy refer to?
Involves radiation
What does the mass peak furthest to the right in a mass spectrum relate to?
The molecular ion M
It’s molecular mass
What leads to fragmentation and what is this?
When an organic molecule is ionised to produce the molecular ion for a mass spectrometer and the energy needed leads to fragmentation of this molecule into lower mass positive ions.
Why is the mass spectrometer unique for every molecule?
Each individual fragment for that molecule is detected by the mass spectrometer
What do the major fragment ions usually include?
The various alkyl groups with can break of the hydrocarbon chain after it is ionised.
