The limiting reactant is determined by comparing the mole ratios of the reactants present in the reaction with the stoichiometric ratios derived from the balanced chemical equation. The reactant that has fewer moles than required by the stoichiometry is the limiting reactant.

Once the limiting reactant is identified, it allows us to calculate the theoretical yield, which is the maximum amount of product that can be obtained based on the amount of limiting reactant present. The theoretical yield provides an ideal value for comparison with the actual yield obtained in the laboratory.

Understanding and identifying the limiting reactant is crucial in chemical calculations as it helps us predict and optimize the yield of a reaction. It allows us to determine the most efficient use of reactants and enables us to avoid wasting resources or producing unwanted byproducts.

Moreover, the concept of limiting reactants is closely related to the concept of excess reactants. The excess reactant is the reactant that is present in surplus amounts after the limiting reactant is completely consumed. It is important to consider the excess reactant when calculating the actual yield of a reaction or determining the amount of reactant that remains unreacted.