🧪 Understanding Chemical Equations

What is a chemical equation? A chemical equation shows what happens during a chemical reaction. The substances that react are called reactants (on the left side), and the new substances formed are called products (on the right side).

Example: H₂ + O₂ → H₂O (This means hydrogen gas plus oxygen gas makes water)

Why do we balance equations? We balance chemical equations because atoms cannot be created or destroyed in a chemical reaction. The same number of each type of atom must be on both sides of the equation.

⚖️ Balancing Practice

How to balance: Add numbers (called coefficients) in front of the chemical formulas to make the same number of each type of atom on both sides. Never change the small numbers in the formulas!

Example: H₂ + O₂ → H₂O becomes 2H₂ + O₂ → 2H₂O

_____ Mg + _____ O₂ → _____ MgO

_____ H₂ + _____ Cl₂ → _____ HCl

_____ Na + _____ H₂O → _____ NaOH + _____ H₂

_____ Ca + _____ O₂ → _____ CaO

🎯 Challenge Problems

_____ Al + _____ O₂ → _____ Al₂O₃

_____ CH₄ + _____ O₂ → _____ CO₂ + _____ H₂O

📝 Answer Key

1. Reactants

2. Produces or makes

3. Because atoms cannot be created or destroyed, so we need the same number of each type of atom on both sides

4. 2 Mg + 1 O₂ → 2 MgO

5. 1 H₂ + 1 Cl₂ → 2 HCl

6. 2 Na + 2 H₂O → 2 NaOH + 1 H₂

7. 2 Ca + 1 O₂ → 2 CaO

8. 2H₂ + O₂ → 2H₂O

9. 4 Al + 3 O₂ → 2 Al₂O₃

10. 1 CH₄ + 2 O₂ → 1 CO₂ + 2 H₂O