Balance Fe + O₂ + H₂O → Fe(OH)₃
4 Fe(s) + 3 O₂(g) + 6 H₂O(l) → 4 Fe(OH)₃(s)
Balance an equation
4Fe(s)+3O₂(g)+6H₂O(l)→4Fe(OH)₃(s)
Balanced
Atoms on each side
| Atom | As writtenleft : right | Balancedleft : right |
|---|---|---|
| Fe | 1:1 | 4:4 |
| O | 3:3 | 12:12 |
| H | 2:3 | 12:12 |
Check atoms
How to balance it, step by step
- Count the atoms of each element on both sides, as written.
- Start with the biggest formula, Fe(OH)₃: put 1 in front of it.
- Fe: 1 on the right. Put 1 in front of Fe.
- H: 3 on the right. Put 3/2 in front of H₂O (3/2 × 2 = 3).
- O: 3 on the right, 3/2 already on the left. Put 3/4 in front of O₂ (3/4 × 2 = 3/2).
- Clear the fraction: multiply every coefficient by 4.
- Check: Fe 4 = 4, O 12 = 12, H 12 = 12. Balanced.
What happens
It is a redox reaction: one substance is oxidised while another is reduced. Iron rusts only when both oxygen and water are present. Rust is hydrated iron(III) oxide, Fe₂O₃·xH₂O, written here as Fe(OH)₃ so that it balances with whole numbers.
Rusting of iron: quick answers
What is the balanced equation for rusting of iron?
4 Fe(s) + 3 O₂(g) + 6 H₂O(l) → 4 Fe(OH)₃(s). The coefficients are 4, 3, 6 and 4. Each side then has 4 Fe, 12 O and 12 H.
What type of reaction is rusting of iron?
It is a redox reaction: one substance is oxidised while another is reduced. Iron rusts only when both oxygen and water are present. Rust is hydrated iron(III) oxide, Fe₂O₃·xH₂O, written here as Fe(OH)₃ so that it balances with whole numbers.
How do you balance Fe + O₂ + H₂O → Fe(OH)₃?
Start with the biggest formula, Fe(OH)₃: put 1 in front of it. Fe: 1 on the right. Put 1 in front of Fe. H: 3 on the right. Put 3/2 in front of H₂O (3/2 × 2 = 3). O: 3 on the right, 3/2 already on the left. Put 3/4 in front of O₂ (3/4 × 2 = 3/2). Clear the fraction: multiply every coefficient by 4. Never change a subscript, because that would change the substance.