c8 - chemical analysis

• define a pure substance

  a single element or compound not mixed with any other substance
• difference between pure substances and impure substances

  • pure substances melt and boil at specific temperatures
  • impure substances melt and boil at a range of temperatures
• define formulation


  mixtures that have been prepared using a specific formula
• types of formulations

  • fuels
  • cleaning agents
  • paints
  • medicine
  • alloys
  • fertilisers
  • foods
• test for gases: hydrogen

  the lit splint will produce a squeaky pop sound in test tube
• test for gases: oxygen

  will relight a glowing splint
• test for gases: chlorine

  bleaches blue litmus paper (blue-red-white)
• test for gases: carbon dioxide

  causes limewater to turn cloudy when bubbled through it
• RF VALUE = distance substance moved / distance mobile phase moved
• define paper chromatography


  use of separating mixtures to help identify substances
• in paper chromatography the mobile phase (solvent - water) will move up the stationary phase (chromatography paper)