Lab practical study guide Flashcards
what if melting point capillary has too much sample
broad melting point range
where is the organic layer in sep funnel
top
where is halogenated organic in sep funnel
bottom
where is non-halogenated organic in sep funnel
top
where is polar material in sep funnel
bottom
where is non-polar material in sep funnel
top
what layer is an acid w organic solvent
organic layer
what layer is base w organic solvent
aqueous layer
what causes low melting point
impurities, wet sample, amount of sample in tube
what to do if crystals don’t form in recrystallization
-scratch flask w stir rod
-concentrate solution by boiling off solvent
-use crystals as seeds
what to do if too much drying agent used
-decant or gravity filter
-rinse drying agent w fresh solvent and combine risings with fresh solution
what happens if too much drying agent is used
will reduce percent yield
Best way to measure 1mL of liquid
pipette w/ bulb
best way to measure 10 mL of liquid
graduated cylinder
best way to measure 0.01g
weigh paper and analytical balance
how would you purify 40mg of solid that has a byproduct present
column chromatography
purify 4g of solid that is 95% pure
recrystallization
purify 40mL of liquid that is 80% pure
simple distillation
seperate two liquids with 5 degree difference in BP if i had 100mg
fractional distillation
separate two liquids with 5 degree difference if had 100 mL
vacuum distillation
***how would you isolate a temp sensitive extract present as 5% component from natural matrix
extraction, TLC
**best apparatus for reducing from C=O to C-OH
heat under reflux
best apparatus for an unknown solid
melting point analysis
best for isomers of a compound with same functional groups
NMR
**best for small reaction mixture to get Keq
UV
where does IR data come from
oscillation of molecular dipoles
what does IR data tell us
functional groups
where does NMR data come from
uses magnetic properties
what does NMR tell us
spin states, shielding, and peaks
where does GC data come from
separation within column
what does GC data tell us
conformation and structural properties
where does GC/MS data come from
mass: charge ratio
what does GC/MS data tell us
detect tiny sample amounts
where does UV data come from
e- moving from high to low orbital
what does UV data tell us
electronic transitions and structure
what is refluxing
boiling of a solution while continually condensing the vapor by cooling and returning ot reaction flask
what is extraction used for
separate an organic product from a reaction mixture
what is distillation used for
purify liquids
stationary phase
silica gel
mobile phase
solvent or mixture of solvents
simple distillation
less surface area, less accurate
fractional distillation
-more surface area, more accurate
-condense and evaporate repeatedly
