Physical Science

• Limiting Reactant


  The reactant that is completely used-up or consumed in a chemical reaction, limiting the amount of product formed
• Excess Reactant


  The reactant other than the limiting reactant, that is left-over after the chemical reaction
• How to Find the Limiting Reactant

  1. Write down the known and unknown quantities

  2. Balance the chemical equation

  3. Convert mass of reactants to moles

  4. Calculate the mole ratio of the reactants

  5. Compare the actual ratio to the stoichiometric ratio
• How to Get the Amount of Product Formed

  Use the calculated amount of moles of the limiting reactant to determine the moles of product formed, then convert to mass
• How to get the Excess Reactant

  1. Moles of limiting reactant x mole ratio of the excess & limiting reactant x molar mass of excess reactant

  2. Subtract the mass of excess reactant from the given
• Percent Yield


  The ratio of the actual yield (amount of product from the experiment) to the theoretical yield, expressed as a percentage
• The theoretical yield is the maximum quantity of a product derived from a given quantity of reactant
• The actual yield is the amount of a product produced when an experiment is performed