Balancing Equations
Year 8 ⚗️ Chemical Reactions Balance symbol equations and use state symbols (s), (l), (g), (aq).
⚖️ Symbol Equations
A symbol equation uses chemical formulas and must be balanced — the same number of each atom on both sides.
Balancing Example
$$\text{Unbalanced: } H_2 + O_2 \rightarrow H_2O$$
$$\text{Balanced: } 2H_2 + O_2 \rightarrow 2H_2O \checkmark$$🏷️ State Symbols
| Symbol | Meaning | Example |
|---|---|---|
| (s) | Solid | NaCl(s) |
| (l) | Liquid | H₂O(l) |
| (g) | Gas | CO₂(g) |
| (aq) | Aqueous (dissolved in water) | HCl(aq) |
📝 Balancing Strategy
- Write the unbalanced equation with correct formulas.
- Count atoms of each element on each side.
- Add coefficients (whole numbers) in front of formulas to balance — never change subscripts!
- Check all atoms balance; simplify coefficients if needed.
2Fe + 3Cl₂ → 2FeCl₃: Fe: 2=2 ✓, Cl: 6=6 ✓
Ready to test yourself? Click the Quiz tab above to practise questions on this topic!
Interactive Demonstration — Balancing Equations
Check if each equation is balanced. Count atoms on each side.
Is each equation balanced?
⚖️ Equation Balancer
Calculate masses from mole ratios in a balanced equation.