Sedimentation, Decantation, Filtration, Evaporation, Crystallization, Sublimation YouTube Lecture Handouts

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Sedimentation, Decantation, Filtration, Evaporation, Crystallization, Sublimation | Separation of Mixture
  • Separation process is a method that converts a mixture or solution of substances into two or more distinct product mixtures.
  • When two or more substances are mixed together form a mixture.
  • Why Separation is essential? As some components may not be useful or may spoil the useful component of the mixture.



Insoluble Substance & Liquid

Sand and Water

Sand and Water
  • Separation process in which solids are separated from the liquid.
  • All the solids settle down at the bottom of a beaker and on top, a clear layer of liquid is obtained.
  • Example: Mixture of sand and water where sand settles down at the bottom.
  • Allowing particles to settle

What Settles down in Sediment

Liquid Above is Supernatant

Can fasten sedimentation by loading or coagulation – rate of sedimentation of mud can be fastened by adding alum or phitkari – alum dissolves in water and binds the mud together – mud particles become heavier and settle quickly.


Separate Water from Sand

Separate Water from Sand
  • Separation of liquid components of a mixture while solid component has settled at the bottom as sediments, that is, transferring a liquid from another container.
  • Example: When water is separated from the mixture of sand and water

Pouring without disturbing - brewing of tea


Whatman Filter Paper?

Sieve vs. Filter

Filter Paper
  • Separation process in which insoluble impurities are separated from the solution
  • Filtration is done with the help of filter paper
  • Example: Filtering mud from muddy water
  • Example: Mixture of sand and water. Filtration is used here to remove solid particles from the liquid.
  • Insoluble material remains in filter paper - clear water passes down
  • Occurs by filter paper, fine sieve or strainer
  • In laboratory we use Whatman filter Paper – circular in shape and can be folded
    • Sieve is single layer woven mesh
    • Filter is multilayer woven mesh
  • Air conditioners, air purifiers, vacuum cleaners use filter to remove dust


Below BP?

  • Changing liquid to gas at temperature below its boiling point is evaporation
    • Heating increases rate of evaporation
    • Salt can be separated from salt solution
    • Separate solid from homogenous mixture


Controlled Evaporation

Is it a controlled evaporation?

Fond of having Sugar in Tea? How is it formed?

Crystal is solid with fixed geometrical shape

  • Crystallization is method of separation and purification in which crystal of solid solute is obtained from solution.
  • Solution is 1st heated to increase rate of evaporation – when little is left, heated solution is allowed to evaporate slowly
  • Small crystals begin to develop and grow in size
  • Pure sugar crystals are formed this way
  • Also used in separating and purifying drugs in pharmaceutical industry

Magnetic Separation

Separate Iron from sulphur

Separate Iron from Sulphur

Separate magnetic and non-magnetic components


Change solid to gas directly

Camphor, naphthalene, iodine, ammonium chloride

Change Solid to Gas Directly
  • Separate ammonium chloride and sand by sublimation - on heating ammonium chloride will sublime and leave sand behind
  • Vapor on cooling changes to crystal - also used for purification of certain compounds
  • Separation is done on size, shape, mass, density, solubility – separation method should be economical as well.

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