C2.1.5 - Distillation Flashcards
What is simple distillation?
The process of separating a solvent from a solution
What does it rely on?
Th e solvent having a much lower boiling point than the solute
What happens when the solution is heated?
The solvent boils but the solute does not
Once it escapes, what is done?
It is cooled and condensed back to its liquid state by a condenser
How is the condenser kept cold?
A flow of cold water
When is simple distillation useful?
If you want to purify a solvent
Name an example of when it can be useful
Getting pure water, as tap water contains sodium chloride and other salts which can interfere with chemical tests
What is all the apparatus used for simple distillation?
Heat Source Rounded flask Vaporising column Thermometer Condenser Beaker
What is fractional distillation?
The process of separating two or more substances from a mixture in the liquid state
What does it rely on?
Each substance having a different boiling point
What special equipment does it use?
It uses the fractionating column
How is fractional distillation used?
It is used industrially to separate different liquids
Give an example of how fractional distillation is used
Separating water and bioethanol to create fuel
What happens in the fractional column?
The vapours condenser on the inside surface, heating it up.
When the temperature inside reaches the boiling point of substance A, it’s vapour cannot condenser any more, yet substance B’s can.
Substance B’s droplets fall back into the flask, and substance A vapour
passes into the condenser
Could you do fractional distillation without the fractionating column?
Yes, but the fractionating column improves the separation of the mixture. It has a large surface area on which the vapours can continually condense. It is hottest at the bottom and coldest at the top
