Balancing Chemical Equations

Importance of Balancing

• To describe chemical reactions accurately.
• Ensures same number of atoms of each element on both sides of the equation.
• Reflects the law of conservation of mass: Atoms are neither created nor destroyed, only rearranged.

Example: Combustion of Methane

• Coefficients: 1 CH₄, 2 O₂, 1 CO₂, 2 H₂O.
  • 1 Carbon Atom on each side.
  • 4 Hydrogen Atoms on each side.
  • 4 Oxygen Atoms on each side.
• Balanced equation: Same number of each atom type on both sides.

Example: Electrolysis of Water

• Initial unbalanced equation: H₂O → H₂ + O₂.
• Balancing Steps:
  1. Hydrogen: 2 atoms on the left, 2 on the right.
  2. Oxygen: 1 atom on the left, 2 on the right.
     • Place a 2 in front of H₂O → 2 H₂O.
     • Results in 4 Hydrogen atoms on the left.
  3. Balancing Hydrogen: Place a 2 in front of H₂ → 2 H₂.
• Final balanced equation: 2 H₂O → 2 H₂ + O₂.

Example: Reaction with Nitrogen and Oxygen

• Initial issue: 2:5 ratio of Oxygen.
  • Place a 5 in front of one compound, and a 2 in front of another.
• Nitrogen becomes unbalanced:
  • After adjusting Oxygen, Nitrogen becomes 4 on product side.
  • Balance by placing a 2 in front of Nitrogen on reactant side.

Conclusion

• Balancing chemical equations involves adjusting coefficients to ensure the same number of each type of atom on both sides.
• Practice with different equations to master this skill.