Chemistry Cheat Sheet: Chemical Equation Balancing

Quick reference guide for balancing chemical equations - Free to print and share!

5-Step Balancing Process

1

Write Equation

Write unbalanced chemical equation

2

Count Atoms

Count each element on both sides

3

Add Coefficients

Balance each element systematically

4

Check Balance

Verify all elements are equal

5

Simplify

Use smallest whole numbers

Golden Rules

✅ DO:

  • • Change coefficients only
  • • Start with most complex molecule
  • • Balance metals first
  • • Save H and O for last
  • • Use fractions, then multiply
  • • Check your work twice

❌ DON'T:

  • • Change chemical formulas
  • • Change subscripts
  • • Add new compounds
  • • Use decimal coefficients
  • • Forget polyatomic ions
  • • Rush the process

Reaction Types & Patterns

Synthesis: A + B → AB

2H₂ + O₂ → 2H₂O

Decomposition: AB → A + B

2H₂O₂ → 2H₂O + O₂

Single Displacement: A + BC → AC + B

Zn + CuSO₄ → ZnSO₄ + Cu

Double Displacement: AB + CD → AD + CB

AgNO₃ + NaCl → AgCl + NaNO₃

Combustion: CₓHᵧ + O₂ → CO₂ + H₂O

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Quick Examples

Easy:

H₂ + Cl₂ → 2HCl

Medium:

2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu

Hard:

C₄H₁₀ + 13/2O₂ → 4CO₂ + 5H₂O

Complex:

Ca₃(PO₄)₂ + 3H₂SO₄ → 3CaSO₄ + 2H₃PO₄

Memory Aids & Tips

Balancing Order Mnemonic:

"Most Complex Metals, Non-metals, Hydrogen, Oxygen"

Remember: MCMNHO - Start with the most complex molecule, then metals, non-metals, hydrogen, and oxygen last.

Common Polyatomic Ions:

SO₄²⁻ (sulfate) NO₃⁻ (nitrate) PO₄³⁻ (phosphate) OH⁻ (hydroxide) CO₃²⁻ (carbonate) NH₄⁺ (ammonium) ClO₃⁻ (chlorate) HCO₃⁻ (bicarbonate)

Need help balancing equations? Use our free online tool:

ChemEqBalancer.com

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