exit prelim Flashcards
alcohols are less volatile than their isomeric ethers because
they have hydrogen bonding
what charge do ion fragments hold
positive ones
which analytical technique relies on the vibrations within molecules
infrared spectroscopy
what technique is used to calculate the calcium ions in milk
complexometric analysis
what technique is used to calculate the chloride ions in sea water
gravimetric analysis
what technique could be used to calculate ethanoic acid in vinegar, and ethanol in wine
volumetric analysis
how can you confirm the identity of a product
mixed melting point analysis, infrared spectra, nmr, tlc
how can you confirm the identity of a product
mixed melting point analysis, infrared spectra, nmr, tlc
what piece of apparatus can be used to separate two layers
a separating funnel
what does it mean if something is measured accurately approximately
the exact mass should be known and should be close to the desired reading
what must be included in a diagram showing heating under reflux
be cross sectional with an inner wall shown
be an open system
be sealed around the flask neck
have water going in at the bottom and out at the top
what are the steps in recrystallisation
dissolve in minimum volume of hot solvent. filter to remove impurities and then cool
why would you heat something under reflux
to prevent vapours escaping, and to allow extended heating. more efficient.
Describe fully the procedure required to obtain results that
would allow a calibration graph to be drawn
Standard/accurate/solutions or
solutions of known concentration
(are prepared/used).
A suitable filter/wavelength/colour
used.
Mention of a blank or solvent only
measurement.
Absorbance/transmittance of each
solution is measured/plotted.
why do different bonds absorb different wavelengths of IR radiation
they have different types of vibration or bend
