Monday, 21 January 2013

Mixture & Compound.Alloy.Separation Techniques 1 21/1/13

Revision: Element, Compound & Mixture

Example of a mixture of elements
Example of a mixture of compounds




Alloy:

  • MIXTURE
  • Mixture of metals with other elements
  • Stronger. Not malleable
* STEEL
   STAINLESS STEEL
   BRONZE
   COPPER   MUST KNOW-S!


Separation Techniques
  • Used only for Mixture
  • Physical Means
  1.          Magnetic Attraction
  2.          Filtration
  3.          Use of separatin funnel
  4.          Distillation
  5.          Crystallization
  6.          Evaporation
  7.          Sublimation
Method used depends on element's properties. e.g. soluble/insoluble

Mixture needs to be separated into pure substance for...
  • Characterization (identify properties)
  • Identification ^
  • Production of useful substances such as medicine


Paper Chromatography

  • separate a mixture of solutes with different solubility and degree of absorption
  • The method uses a solvent moving over a porous or absorbent medium
Solvent : Water / ethanol

Principle ( Uncompleted)
  • As solvent travels up the paper, the dyes dissolved
  • some dyes are more soluble, so they travel faster up the paper
  • dyes that are less soluble remain as the bottom of the paper (own comment)
example of a paper chromatography experiment




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