Purity and Formulations

• Purity (in everyday use)

  Nothing has been added to a substance, it's in its natural state
• Purity (in chemistry)


  A substance that only contains one compound or element all the way through, not mixed with anything else
• Melting or boiling point


  Tells you how pure a substance is
• Testing purity of a known substance


  1. Measure melting or boiling point

  2. Compare to data book value

  3. The closer the measured value is to the actual melting/boiling point, the purer the sample
• Impurities in a sample


  Lower the melting point and cause the sample to melt across a wider range of temperatures
• Impurities in a sample

  Increase the boiling point and cause the sample to boil across a range of temperatures
• Formulations


  Useful mixtures that have been designed for a particular use
• Making formulations


  1. Follow a 'formula' (recipe)

  2. Carefully measure each part so the formulation has the right properties to work as intended
• Formulations can be found in cleaning products, fuels, medicines, cosmetics, fertilisers, metal alloys, food and drink