Percentage Yield

• Atoms are never lost or gained in a chemical reaction
• It is not always possible to obtain the calculated amount of product:

  • If the reaction is reversible , it may not go to completion (Some of the product may turn back into the reactants)
  • Some of the product could be lost when separated from the reaction mixture 
  • Some of the reactants may react in different ways to the expected reaction
• The amount of product obtained is called the yield
• The percentage yield can be calculated by using the formula

  Percentage yield = ( yield from reaction / maximum theoretical yield ) x 100