Evaluating reactions: Quantitive Chemistry: Chemistry: GCSE (9:1)

• Theoretical yield


  The maximum amount of product that can be made
• Actual yield

  The amount of product made by carrying out the reaction
• Percentage yield equation

  Actual yield/theoretical yield x 100

  
• Reasons % yield is less than 100%

  Reversible reaction, product is lost, side reactions
• Reversible reaction

  A chemical reaction in which the products re-form the original reactants

  
• Ways product is lost

  Stuck in the reaction vessel, or by separation from the reaction mixture
• Side reactions

  Reactions that do not give the desired product of a reaction
• Definition of atom economy

  A measure of the number of atoms in the starting materials that end up as useful products
• Formula for atom economy

  Formula mass of desired product/formula mass of all reactants x100

  
• 100% atom economy


  All the atoms in the reactant have been turned into useful products
• Use of percentage yield and atom economy


  To measure the waste and efficiency of a reaction
• Improve atom economy

  Use a better reaction, sell side products.