purity and formulations

• Pure substance


  A single element or a single compound, not mixed with any other substance
• Pure substance


  • Melts at a specific fixed temperature
  • Boils at a specific fixed temperature
• Determining if a substance is pure

  1. Measure melting point

  2. Measure boiling point
• Pure substances

  • Pure silicon
  • Pure sodium chloride
• Impure substance


  Melts and boils over a range of temperatures
• Impure substance


  • Mixture of water and impurity
• Formulation


  A complex mixture that's been designed as a useful product, with carefully measured quantities of each component
• Scientists often produce mixtures called formulations