Equal atoms on both sides
See each coefficient change
Combustion, synthesis, etc.
Understand mole ratios
Select an equation and click "Balance Equation" to see the step-by-step balancing
Click "Balance Equation" to begin balancing the chemical equation.
Complete the balancing to see the final equation.
Balance elements that appear in only one reactant and one product first.
// Fe + O₂ → Fe₂O₃
// Step 1: Balance Fe (2 on right)
2Fe + O₂ → Fe₂O₃
// Step 2: Balance O (3 on right, 2 on left)
// Use coefficients: 4Fe + 3O₂ → 2Fe₂O₃Never change subscripts in chemical formulas - only adjust coefficients!
// WRONG: Changing H₂O to H₂O₂
H₂ + O₂ → H₂O₂ ✗
// CORRECT: Use coefficient
2H₂ + O₂ → 2H₂O ✓The Law of Conservation of Mass states that matter cannot be created or destroyed. In a chemical reaction, all atoms present in the reactants must be accounted for in the products.
Coefficients (numbers in front) multiply the entire molecule and can be changed. Subscripts (small numbers after elements) indicate atom count within a molecule and cannot be changed without changing the substance.
Stoichiometry is the calculation of reactants and products in chemical reactions. It uses the mole ratios from balanced equations to determine quantities needed or produced.