The mole ratio in a chemical equation is the ratio of the amounts (in moles) of reactants and products as shown by their coefficients in a balanced chemical equation.
It tells us the relative number of molecules or moles that react or are produced. These ratios come directly from the balanced equation and are used in stoichiometry to calculate how much of one substance is needed or formed from another.
For example:
2H₂ + O₂ → 2H₂O
- The mole ratio of H₂ to O₂ is 2:1.
- The mole ratio of H₂ to H₂O is 2:2 (or 1:1).
- The mole ratio of O₂ to H₂O is 1:2.
This means 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water.