Learning Objectives
- Atoms are conserved in reactions.
- Coefficients change molecule counts.
- Subscripts do not change during balancing.
ChemistryMiddle / High School14 min
Balancing Chemical Equations
Practice conservation of atoms through four school-level equations.
H₂ + O₂ → H₂O
1H₂
1O₂
1H₂O
H: 2 | 2
O: 2 | 1
Atoms are not equal yet.
Live Values
H
2 = 2
O
2 = 1
Formula
left atoms = right atoms
Change coefficients only; do not change subscripts inside formulas.
Try this
Balance the equation without using the hint, then check atom counts.
| Atom | Left | Right |
|---|---|---|
| H | 2 | 2 |
| O | 2 | 1 |
Almost there. Only one atom type is still unmatched.
Conservation of atoms
What happened?
When each atom type has equal counts on both sides, the equation is balanced.
Why?
A coefficient changes whole molecule counts; a subscript belongs to the compound formula and is not changed.
Tags
CoefficientsAtom countConservationHint