Periodic Table/Tools/Stoichiometry Calculator

Stoichiometry Calculator

Enter a balanced equation and a known amount to calculate all reactant and product quantities. Toggle limiting reagent mode for multi-reactant analysis.

Examples:
2H2+O2→2H2O

Results

SubstanceCoeffMolesGramsLiters (STP)*
RH2known
21.0000002.016022.4140
RO2
10.50000015.999011.2070
PH2O
21.00000018.015022.4140

Step-by-Step Calculation

  1. 1.Known: 1.000000 mol of H2
  2. 2.Moles of O2: 1.000000 mol H2 × (1 mol O2 / 2 mol H2) = 0.500000 mol
  3. 3.Moles of H2O: 1.000000 mol H2 × (2 mol H2O / 2 mol H2) = 1.000000 mol
  4. 4.Convert moles to grams using molar masses and to liters using 22.414 L/mol at STP.

Molar Mass Reference

H22.016 g/mol
O231.998 g/mol
H2O18.015 g/mol

* Liters at STP assumes ideal gas behavior (0 °C, 1 atm, 22.414 L/mol). Only meaningful for gaseous substances. · Atomic weights from IUPAC 2021