Distillation

• Describe process of simple distillation

  
  

  • 1 ) Heat up mixture/solution in flask so liquid evaporates.
  • 2 ) As it rises to the top of flask the pressure will force the vapour to pass into the condenser
  • 3 ) Because there is cold water being pumped through water jacket ( surrounding condenser ) , vapour will cool and condense into liquid form
  • 4 ) This will be collected in the beaker
• Why can you not use simple distillation for mixtures that contain multiple different liquids ?

  If the liquids have similar boiling points, those liquids might evaporate at the same time.
• When would you need to use fractional distillation rather than simple distillation ?

  Separating mixture that contains multiple liquids with similar boiling points.
• What is the fractionating column used in laboratory fraction distillation filled with ? Explain why.

  • Glass rods

  These provide a large surface area which will cause gases to condense back to liquid as the temperature is below their boiling point .
• Mixture of Methanol (65*), Ethanol (76*)and Propanol (97*) Fractional Distillation technique

  • 1 ) Methanol has a boiling point of 65* so heat mixture to 65*
  • 2 )This causes methanol to evaporate + rise up fractionating column
  • 3 ) It passes into condenser and condenses into liquid methanol, which is then collected in beaker
  • 4 ) Repeat process but rise temp. to Ethanol’s boiling point which is 78* allowing us to only evaporate off Ethanol.
  • 5 ) At this point only propanol could be left , so one could just assume it’s pure ethanol but just to be sure…

  - rise temperature to 97* + repeat process!
• What could happen to the other components as the methanol is being fractionally distilled ?

  By chance Ethanol + Propanol might also rise up (evaporate) but as they come into contact w/ glass rods, which are much cooler that it’s boiling point , it’ll condense back into liquid form and fall back into flask; so only liquid getting into beaker is methanol.
• Name And function of component labeled

  Bung ; So no gas can escape.

  
• Feature of section of column labeled 


  • hottest bit of column

  
• Feature of section of column labeled 


  • coolest bit of column

  
• Name + function of component arrowed

  • Condenser ;  to cool the vapours, allowing them to condense to liquid form and be collected.

  
• Name and function of component arrowed

  • Cold water in* (water jacket) carries vapours of boiling liquid.