http://www.csun.edu/~hcchm001/IntroChemHandouts.html A limiting reagent is a chemical reactant that limits the amount of product that is formed. The limiting reagent gives the smallest yield of product calculated from the reagents(reactants) available. This smallest yield of product is called the theoretical yield. To find the limiting reagent and theoretical yield, carry out the following procedure:1. Find the moles of each reactant present.2. Calculate the moles of a product formed from each mole of reactant.3.