• The atom economy of a reaction shows how many of the atoms used in the reaction become the desired product
  • The rest of the atoms or mass is wasted

   

• It is found directly from the balanced equation by calculating the Mr of the desired product

• In addition reactions, the atom economy will always be 100%, because all of the atoms are used to make the desired product
  • Whenever there is only one product, the atom economy will always be 100%

   

• For example, in the reaction between ethene and bromine:

CH2=CH2?+ Br2?→ CH2BrCH2Br

• The atom economy could also be calculated using mass, instead or Mr
• In this case, you would divide the mass of the desired product formed by the total mass of all reactants, and then multiply by 100