fractional distillation

Question 1

what do we use fractional distillation for ?

Answer 1

to separate a mixture of different liquids

2 or more

Question 2

what is the key difference of the liquids that is required in order to carry out fractional distillation?

Answer 2

the boiling points of the different liquids MUST be different

Question 3

what is the flask containing the mixture connected to?

Answer 3

a long column containing hundreds of glass beads

Question 4

what is the long column full of hundreds of glass beads called?

Answer 4

the fractionating column

Question 5

what does the fractionating column do?

Answer 5

when the 2 vapours are in the fractionating column

Question 6

what is at the top of a fractionating column?

Answer 6

a thermometer

Question 7

if we have a boiling point of 2 liquids. one higher than the other.
we then heat the mixture.
which liquid will evaporate more easily?

Answer 7

the liquid with the lower boiling point

Question 8

describe fully how to separate 2 liquids from each other through fractional distillation

Answer 8

1. heat the solution (using a bunsen burner e.g)
2. we heat it til the thermometer shows the boiling point of the chemical with the lower boiling point.
3. the liquid with the lower b.p evaporates and forms a vapour
4. the vapour is carried through the fractionating column
5. when the warm vapour passes up the column, it reaches the thermometer, the temperature of the thermometer then begins to rise
6. once the temperature on the thermometer reaches the boiling point of the chemical with the lower b.p and it stops rising
7. At this point we have 1 pure chemical passing into the condenser and we collect it in the fresh beaker. this is our first proper fraction, the chemical that boils at the lower boiling point.
8. after awhile, the temperature on the thermometer begins to rise again, this means a mixture of vapour is passing into the condenser, but this time it mainly contains the chemical with the higher b.p
9. when the temperature becomes constant, we know we are collecting a relatively pure sample of the chemical into a fresh beaker
10. now the two chemicals have been separated

Question 9

what might affect the difficulty level of separating 2 different liquids?
what would we do in this case?

Answer 9

having a very similiar boiling point

Question 10

why might fractional distillation in this method not a suitable idea for crude oil?

Answer 10

to purify larger volumes through fractional distillation, different equipment is required although the principle stays the same