Separation Techniques

Question 1

Diffusion

Answer 1

High to low conc
Random
Particles randomly hit others
Down conc gradient

Question 2

Diffusion experiments

Answer 2

Potassium permanganate crystals in water
Pp molecules hit water molecules

Ammonia and hydrogen chloride
Cotton balls soaked in tube
Ammonia, less dense, moves faster down
White ring where they meet

Question 3

Filtration

Answer 3

Separate insoluble solid from liquid
Filter paper in funnel, beaker under funnel
Mixture in funnel

Question 4

Evaporation

Answer 4

Separate soluble solids from liquids
Solution heated
Liquid evaporated leaving crystallised solute

Question 5

Chromatography

Answer 5

Separate coloured compounds
Solvent on piece of paper
Placed upright in solvent
Solvent soaks up paper, carries mixture with it
Different components of mixture move at different rates

Question 6

Distillation

Answer 6

Separate a liquid from solution
Solution heated. Part of solution with lowest boiling point evaporates
Vapour cooled, condensed, collected
Rest of solution left behind in flask

Question 7

Fractional distillation

Answer 7

Separate 2 or more liquids with similar boiling points
Mixture heated below fractionating column
All liquids will boil at different temperatures, liquids rise but will fall as they reach cooler parts of the column
Condensed, collected