QUESTIONS GRADED A+
⫸ Solvent pair Answer: A mixture of two solvent that meets the
requirement necessary for successful recrystallization
⫸ Filter Flask Answer: A receiver flask with a sidearm
⫸ Water Aspirator Answer: Water moves past a small hole leading
into a sidearm that can be attached to a trap
⫸ Bernoulli effect Answer: A partial vacuum is created because of the
reduced pressure at the point where the rapidly moving water passes
the hole. At that point, air is pulled into the aspirator sidearm.
⫸ Trap Answer: Can be used in tandem with a water aspirator to
prevent contamination of the solution in the filter flask with water
⫸ Why you should not add boiling chips to a boiling liquid? Answer:
Because the boiling chip could cause the liquid to boil over
⫸ How and why you should position the thermometer in the
distillation head during distillation? Answer: By submerging the bulb
of the thermometer where the vapor is because that position will give
the accurate boiling point
, ⫸ What is the purpose of the outer jacket on a fractionating column?
Answer: Keep heat loss from inner jacket
⫸ What effect does an increasing in the heating rate have on the
boiling temperature during a distillation? Answer: There will be a lot
of heat to the distillation will cause a boil over
⫸ As molecules move up a fractional distillation column, they
condense and revaporize. During which of these steps is the
concentration of the more volatile compound of the mixture
increased? Answer: Concentration of more volatile compound
increases as vapors move up column. Each condensation-
revaporization phase increases concentration of more volatile
compound.
⫸ Distillation Answer: Is a technique widely used in organic
chemistry for separating compounds based on differences in their
boiling point
⫸ Volatile Answer: Have relatively high vapor pressures and low
boiling point.
⫸ Evaporation Answer: Occurs at temperatures below the boiling
point of a compound, involves the transition from liquid to vapor of
only those molecules at the liquid surface.
⫸ Equilibrium vapor pressure Answer: Pressure exerted by gaseous
molecules