Balancing chemical equations is a core skill in Class 10 Chemistry. Here are 20 essential balanced equations covering all major reaction types — with the law of conservation of mass verified for each.
The Law of Conservation of Mass (Lavoisier, 1789) states that mass can neither be created nor destroyed in a chemical reaction. This is WHY equations must be balanced — total atoms must be equal on both sides.
Formation of water: 2H₂ + O₂ → 2H₂O
Formation of ammonia: N₂ + 3H₂ → 2NH₃
Burning of magnesium: 2Mg + O₂ → 2MgO
Formation of calcium oxide (quicklime): 2Ca + O₂ → 2CaO
Iron rusting (simplified): 4Fe + 3O₂ → 2Fe₂O₃
Electrolysis of water: 2H₂O → 2H₂ + O₂
Decomposition of calcium carbonate (limestone): CaCO₃ → CaO + CO₂
Decomposition of silver chloride (in sunlight): 2AgCl → 2Ag + Cl₂
Decomposition of ferrous sulphate: 2FeSO₄ → Fe₂O₃ + SO₂ + SO₃
Decomposition of lead nitrate: 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂
Zinc displaces copper: Zn + CuSO₄ → ZnSO₄ + Cu
Iron displaces copper: Fe + CuSO₄ → FeSO₄ + Cu
Sodium in water: 2Na + 2H₂O → 2NaOH + H₂
Zinc with dilute H₂SO₄: Zn + H₂SO₄ → ZnSO₄ + H₂
Magnesium with HCl: Mg + 2HCl → MgCl₂ + H₂
Neutralisation (NaOH + HCl): NaOH + HCl → NaCl + H₂O
Precipitation (silver nitrate + sodium chloride): AgNO₃ + NaCl → AgCl↓ + NaNO₃
Combustion of methane: CH₄ + 2O₂ → CO₂ + 2H₂O
Combustion of ethanol: C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Steps:
Example: Balance H₂ + O₂ → H₂O
**2Mg + O₂ → 2MgO**. Magnesium burns with a brilliant white flame producing white magnesium oxide powder. This is an exothermic combination reaction.
Why is Graphite a Good Conductor of Electricity?
Learn why graphite conducts electricity despite being a non-metal. Understand its layered structure, delocalized pi electrons, and how it differs from diamond.
What Is the Chemical Name of H2O?
H2O is the chemical formula for water. Its IUPAC name is oxidane. Molecular mass is 18 g/mol. Learn formula, properties, and uses of water.
Why Is H₂S Less Acidic Than H₂Te?
H₂S is less acidic than H₂Te because S–H bond is stronger than Te–H bond. Down Group 16, bond dissociation enthalpy decreases, making H⁺ release easier. Full explanation.
What Happens When Baking Soda Is Heated? NaHCO3 Thermal Decomposition
Heating baking soda (NaHCO3) produces sodium carbonate, water, and CO2: 2NaHCO3 → Na2CO3 + H2O + CO2. Observe effervescence and white residue.
What is a Heterogeneous Mixture? (Definition and Examples)
Learn the definition of a heterogeneous mixture in Chemistry. Explore common daily life examples like oil and water, soil, pizza, and muddy water.
Turn this guide into revision flashcards, a practice exam, or an AI-generated podcast — free, no signup required.