Chemical Equation Balancer

Balancing a chemical equation relies fundamentally on the Law of Conservation of Mass, which dictates that matter cannot be created or destroyed in a chemical reaction. Therefore, the number of atoms for each element on the left-hand side (LHS, representing reactants) must precisely equal the number of atoms for that same element on the right-hand side (RHS, representing products). The calculator analyzes both input sides, sets up a system of linear algebraic equations based on atomic counts, and solves for the lowest whole-number integer coefficients that balance every element present.

Consider the unbalanced combustion reaction of methane, where methane (CH₄) and oxygen gas (O₂) react to form carbon dioxide (CO₂) and water (H₂O). Written as LHS → RHS, we have CH₄ + O₂ → CO₂ + H₂O. First, count the atoms: LHS has 1 carbon, 4 hydrogens, and 2 oxygens; RHS has 1 carbon, 2 hydrogens, and 3 oxygens. To balance the hydrogen atoms, we place a coefficient of 2 in front of H₂O on the RHS, giving 4 hydrogens total. Now, the RHS has 4 oxygens (2 from CO₂ and 2 from H₂O). To match this on the LHS, we place a coefficient of 2 in front of O₂. The fully balanced equation is CH₄ + 2O₂ → CO₂ + 2H₂O.

When working with chemical equations manually or verifying calculator results, always balance polyatomic ions as single units if they remain intact on both sides of the reaction. It is generally easiest to leave hydrogen and oxygen atoms for the very end, as they frequently appear in multiple reactants and products. Finally, double-check that your final coefficients are reduced to their lowest possible whole-number ratios.