RECRYSTALLIZATION - EXERCISE ANSWERS
Five criteria that should be used in selecting a solvent for recrystallization are:
a. The substance being purified must be insoluble or nearly insoluble in cold solvent, but very
soluble in the hot s
GAS CHROMATOGRAPHY - EXERCISE ANSWERS
1. a. The stationary liquid phase is a liquid of low volatility, coated on the surface of a finely divided solid material
in which the components of the mixture selectively dissolve. b. The mobile phase
THIN LAYER CHROMATOGRAPHY - EXERCISE ANSWERS
3. If the sample spot were immersed in the solvent, the components of the mixture would be eluted from
the plate directly into the solvent.
4. If the solvent evaporates from the plate during the
MELTING POINTS - EXERCISE ANSWERS
a. Lower mp: Heating too fast (thermometer lags behind actual temperature of the medium),
and uncalibrated thermometer.
b. Higher mp: Large sample or sample not packed tightly so that heat is not transfe
DISTILLATION - EXERCISE ANSWERS
4. A successful fractional distillation depends upon maintaining a temperature gradient within the column.
Ideally, the temperature at the bottom of the column should be similar to the boiling temperature of
ACID AND BASE EXTRACTION - EXERCISE ANSWERS
The anhydrous sodium sulfate is used to remove the last traces of water that may remain in the organic solvent.
Although the organic solvent was chosen because it is "immiscible" in water, it i
DEHYDRATION OF AN ALCOHOL - EXERCISE ANSWERS
The hydroxyl group of the alcohol is involved in a network of intramolecular hydrogen bonds in
which the hydrogen on one hydroxyl group is attracted to the oxygen atom on another. These intera
CHEMICAL KINETICS - EXERCISE ANSWERS
For an SN1 reaction: rate = k[R-L]
For an SN2 reaction: rate = k[R-L][Nu:]
The kinetics you studied for this experiment was SN1.
Solvolysis refers to a reaction in which a reactant is the solvent r