Identify which reactant runs out first and how much product it permits.
Comparing moles alone is not enough — each must be divided by its stoichiometric coefficient. The smallest result identifies the limiting reactant and sets the extent of reaction. Yield calculations based on the wrong reactant overstate output, and the excess reactant becomes waste that must be separated or disposed of.
Limiting Reactant
Divide each reactant’s moles by its coefficient; the smallest quotient limits the reaction
Divide each reactant’s moles by its coefficient; the smallest quotient limits the reaction Comparing moles alone is not enough — each must be divided by its stoichiometric coefficient. The smallest result identifies the limiting reactant and sets the extent of reaction.
Yield calculations based on the wrong reactant overstate output, and the excess reactant becomes waste that must be separated or disposed of.
This calculator takes 6 inputs: Mass of reactant A, Molar mass of A, Coefficient of A, Mass of reactant B, Molar mass of B, Coefficient of B. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.