Balancing Chemical Equations Lecture

Introduction

• Topic: Balancing chemical equations
• Aim: Learn a method to balance chemical equations
• Pre-requisite: Understanding chemical formulas

Chemical Formula Recap

• Example: Sodium Carbonate
  • Elements: Sodium (Na), Carbon (C), Oxygen (O)
  • Atoms:
    • Sodium: 2 (indicated by the subscript)
    • Carbon: 1
    • Oxygen: 3
• Rule: Never change the small numbers (subscripts) in a chemical formula.
• Use of Large Numbers: A large number in front of a formula indicates multiple molecules (e.g., 3 Na₂CO₃ indicates 3 molecules of sodium carbonate).

Balancing Chemical Equations

• Definition: A balanced chemical equation has the same number of each type of atom on both sides of the equation.
• Example: Calcium + Chlorine → Calcium Chloride
  • Both sides have 1 Calcium atom and 2 Chlorine atoms, thus balanced.

Steps to Balance Equations

1. Count Atoms: Count the number of each type of atom on both sides of the equation.
2. Balance Atoms:
   • Cannot change subscripts.
   • Use large numbers in front to balance atoms.

Example: Sodium + Iodine → Sodium Iodide

• Initial count shows imbalance in Iodine atoms.
• Solution:
  • Add large numbers to balance both Sodium and Iodine atoms.

Practice Problems

• Problem 1: Calcium Oxide + Hydrochloric Acid → Calcium Chloride + Water

  • Identify imbalance in Hydrogen and Chlorine.
  • Add a large 2 to balance.

• Problem 2: Iron Oxide + Carbon Monoxide → Iron + Carbon Dioxide

  • Initial imbalance in Carbon and Oxygen.
  • Add large numbers to achieve balance.

Additional Resources

• More questions available in the revision workbook.

Conclusion

• Balancing chemical equations requires careful counting and adjusting with large numbers.
• Practice with given examples for mastery.