Percentage yield

• Reaction information


  Shown using word and symbol equations
• Mass is conserved in chemical reactions
• No atoms are made or destroyed in chemical reactions
• Relative atomic masses


  Can be used to find the relative formula mass of a compound
• Theoretical yield


  The maximum mass that could be made of a certain product
• Actual yield


  The mass of product made when the reaction is actually carried out
• Calculating percentage yield


  Percentage yield = (mass obtained / expected mass) x 100
• 100% yield means no product has been lost, 0% yield means no product has been made
• Reasons for less than 100% yield


  • Loss when filtering
  • Loss when evaporating
  • Loss when transferring liquids
  • Not all reactants reacting to make product
• Percentage purity


  Calculated by dividing the mass of the pure chemical by the total mass of the sample, and then multiplying this number by 100