6.3.1 Chromotography and 6.3.5 NMR Spectroscopy Flashcards
2 types of chromatography
thin layer and gas
Rf value equation
distance moved by spot/distance moved by solvent
what is the stationary phase
in a fixed place
the molecules interact with stationary phase slow down movement
what is the stationary phase for gas chromatography
liquid on solid support
what is the mobile phase for gas chromatography
gas
what is TLC used for
to check purity/monitor the extent of a reaction
stationary phase of TLC
silica gel
mobile phase of TLC
solvent
when is the Rf value closer to one
when substances are very soluble in liquid
limitations of Rf values
similar compounds have similar Rf values
unknown compounds have no Rf values for comparison
hard to find solvent that has correct amount of solubility
how is separation achieved
by relative adsorptions of substances with the stationary phase
what is gas chromatography used for
separate volatile compounds (gases) in a mixture
what is a volatile compounds
gases so have low boiling points
when is gas chromatography used
in forensic investigations
retention time
time taken to pass through column
what does chemical shift indicate
enviroments carbons are in
3 things obtained from a carbon-13 NMR
number of different carbons
carbon environment
relative ratio of each types of carbons
what is nucleur magnetic resource spectroscopy
technique used to probe the structure of molecules
how are concentrations of components determined
comparing peak integration with values obtained from standard solutions of the component
what is the area under the peaks on proton NMR proportional to
the number of protons
