lesson 5 fractional distillation Flashcards
in fractional distillation what do we do
separate a mixture of different liquids
in fractional distillation, the liquid must have different what
boiling points
in our flask what do we have
a mixture of two different liquids
fractional distillation works as well with how many different liquids in the flask
several different liquids
as long as they have different boiling points, fractional distillation will work
the flask containing our liquid is attached to what
a long column containing hundreds of glass beads
what’s the name of the long column
the fractionating column
at the top of the fractionating column, we have what
a thermometer
we also have a ________ just like simple distillation
condenser
what does cold tap water do around the condenser
circulate
what do we do at the start of fractional distillation (after set up) with two different boiling points
we start by gently heating our mixture
once you gently heat your mixture, what happens
both our liquids will start to evaporate
the liquid with the lower boiling point does what
evaporates more easily
once you evaporate your liquids what do we have
a mixture of two different vapours, making their way into the fractionating column
when the vapours reach the fractionating column, what occurs
they condense and drip back into the flask where the liquids evaporate again
the repeated evaporation and condensation does what
increases the amount of the lower boiling point chemical in the fractionating column
as the warm vapours pass up the column, they reach the
thermometer and the temperature of the thermometer begins to rise
when the temperature is rising, this means that
a mixture of the two different vapours is passing over the thermometer
the mixture that is passing over the thermometer will contain what
more of the chemical with a lower boiling point
after the vapours pass over the thermometer they now pass into the
condenser
once the vapours pass through the condenser, it turns back into a
liquid
once the vapours condenses into a liquid, the liquid is still a mixture of what
the two chemicals
there comes a point when the temperature on the thermometer stops rising which will be the what…
the lower of the two boiling points
at the point of the temperature of the lower of the two boiling points stops rising on the thermometer, what occurs
we only now mainly have one chemical passing into the condenser
as the chemical condenses what can we do with it
collect it in a fresh beaker and that is our first proper fraction
after a while of our first proper fraction, what occurs
the temperature starts to rise again
the temperature rising again awhile after our first proper fraction means what
a mixture of vapours is passing into the condenser
once a mixture of vapours is passing into the condenser awhile after our first proper fraction, the mixture mainly contains what
the chemical with the higher boiling point
when the thermometer reaches a constant temperature what do we collect
a relatively pure sample of the second chemical
if the two liquids have very similar boiling points, what does this mean
that is is much harder to separate and may need to carry several rounds of fraction distillation
