Divide each mole quantity by the smallest to get the ratio.
The molar ratio is the ratio of moles of one substance to another in a balanced chemical equation. It is the bridge between reactants and products in stoichiometric calculations. For 2H₂ + O₂ → 2H₂O, the molar ratio of H₂:O₂:H₂O = 2:1:2. To use it: (1) Convert given mass to moles. (2) Use the molar ratio to find moles of desired substance. (3) Convert back to mass if needed. The limiting reagent is the reactant that runs out first based on the molar ratio — it determines the maximum product yield. Excess reagent remains unreacted. Molar ratios are essential in industrial chemistry for optimizing raw material usage, in analytical chemistry for titration calculations, and in pharmaceutical manufacturing for drug synthesis.