Chemical equation balancer
Write the reactants and products and the app balances the equation, checks the atoms on each side, finds what is oxidized and reduced and, for known reactions, gives ΔH°, ΔS°, ΔG° and K. Free in Periodic Table and Chemistry.
How to balance a chemical equation
- Write the unbalanced equation with correct formulas: CH₄ + O₂ → CO₂ + H₂O.
- Balance the elements that appear in only one compound on each side first. Carbon: 1 = 1.
- Then hydrogen: 4 H on the left needs 2 H₂O on the right.
- Leave elements that appear alone for last. Oxygen: the right now has 2 + 2 = 4 O, so the left needs 2 O₂.
- Check every element: C 1 = 1, H 4 = 4, O 4 = 4.
Worked example: combustion of methane
| Step | Result |
|---|---|
| Balanced | CH₄ + 2 O₂ → CO₂ + 2 H₂O |
| Atoms on each side | C 1 = 1 · H 4 = 4 · O 4 = 4 |
| Oxidized | C: −4 → +4 (CH₄ → CO₂) |
| Reduced | O: 0 → −2 (O₂ → CO₂) |
| ΔS° at 25 °C | −5.3 J/(mol·K) |
| ΔH° at 25 °C | −802.6 kJ/mol |
Thermodynamics uses the physical states from the app’s reaction catalog (here, water as a gas). CH₄ is the reducing agent and O₂ the oxidizing agent.
What the app does for you
- Balances any equation you type, and shows the atoms on each side so you can check it.
- Redox by the ion-electron (half-reaction) method, in acidic or basic medium, with oxidation numbers, oxidizing and reducing agents.
- ΔH°, ΔS°, ΔG° and K at 25 °C when the reaction is in the catalog of 147 reactions, which also opens in the balancer with one tap.
- With Pro: stoichiometry, with the limiting reactant and the yield.
Questions.
- Is the equation balancer free?
- Yes. Balancing, redox by the half-reaction method and the thermodynamics of catalog reactions are free. Stoichiometry (limiting reactant and yield) is part of Pro.
- Can it balance ionic redox equations?
- Yes. Write the ionic skeleton and choose acidic or basic medium: the app adds H⁺, OH⁻ and H₂O by the ion-electron method.
- Where do ΔH° and ΔS° come from?
- From standard thermodynamic data at 25 °C for each species, in the physical states listed in the app’s reaction catalog.
More chemistry calculators.
Try it on your iPhone.
Free on the App Store for iPhone, iPad, Mac and Apple Watch.