1. Stoichiometry

Limiting and Excess Reactants: The reactant that is completely consumed when a reaction is run to completion is known as the limiting reactant. The other reactants are termed as excess reactants.

• To find the limiting reactant: First, balance the stoichiometric equation. Then, take the ratio of the reactant feed rate to their stoichiometric coefficients. The limiting reactant is the reactant that has the lowest ratio.

Fractional Excess: The fractional excess of a reactant is the ratio of excess to the stoichiometric requirement. \[\text{Fractional excess of $A$} = \frac{n_A \text{ in feed} - n_A \text{ stoichiometric}}{n_A \text{ stoichiometric}}\] ‘\(n_A\)’ is the number of moles of \(A\)—the reactant. ‘\(n_A\) stoichiometric’ is the amount of \(A\) needed, to react completely with the limiting reactant.