separation techniques

• common substances that sublime

  iodine, ammonium chloride, solid carbon dioxide
• filtration is used to separate a mixture of an insoluble liquid and a liquid
• a separating funnel is used to separate immiscible liquids
• residue


  solid remaining on the filter
• filtrate 


  liquid that passes through the filter
• crystallisation is used to recover a soluble solid from a liquid

  
  

  keywords: saturation, cooled, drying
• crystallisation is used for substances whose solubility differs appreciably with temperature and decompose on heating
• evaporation to dryness is used to recover a soluble solid from a liquid
• evaporation to dryness is used to recover solutes whose solubility do not change much with temperature and do not decompose on heating
• sublimation is the process where a substance in the solid state changes to the gaseous state without passing through the liquid state
• sublimation is used to separate a solid mixture of a sublimable component from a non sublimable component by heating the mixture
• simple distillation is used to recover a liquid from a mixture of a soluble solid and a liquid
• fractional distillation is used to separate a mixture of miscible liquids
• chromatography is used to separate and identify small amounts of substances that are dissolved in solvents. they are separated due to differences in solubility in a particular solvent. a more soluble substance will travel further and faster
• retention factor (Rf) is calculated using the formula distance travelled by the substance / distance travelled by the solvent
• a locating agent is a chemical that can make colourless substances visible
• paper chromatography can be used to determine the purity of a substance