Chemical Equation Balancer
Practise with 1,700+ real equations, or type your own and balance it with charges.
Separate species with + (spaces around the plus). Use plain numbers for subscripts: Ca(OH)2. For ions write the charge with a caret: Cu^2+, Fe^3+, e^-, SO4^2-. Charge is balanced too.
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Things to try
- Pick Hard and Combustion, then balance a large hydrocarbon.
- Switch to Your own equation and type MnO4^- + Fe^2+ + H^+ -> Mn^2+ + Fe^3+ + H2O. Charge must balance too.
- Use Hint when stuck, and try to finish a streak of five without help.
- Filter by Acid-base to practise neutralisation reactions.
What you can learn
- Atoms are neither created nor destroyed, so both sides need the same count of each element.
- Change coefficients, never the subscripts inside a formula.
- Balance elements that appear in one compound on each side first, and leave O and H for last.
Frequently asked questions
Why can't I change the subscripts to balance an equation?
Subscripts define what the substance is. Changing H₂O to H₂O₂ makes hydrogen peroxide, a different compound. Only coefficients can change.
What is the law of conservation of mass?
In a chemical reaction the total mass of the reactants equals the total mass of the products, because atoms are only rearranged.