Lecture Notes (Unit 7) 3/13

Principles of Balancing Chemical Equations

• To achieve a balanced chemical equation, follow these key principles:

  • Smallest Total Number Coefficients: Always use the smallest total number of coefficients to balance the equation. This helps maintain clarity and consistency in stoichiometric calculations.

  • Equal Number of Atoms: Ensure that the number of each type of atom is equal on both sides of the equation, adhering to the Law of Conservation of Mass.

Combustion Reaction Example

• When balancing combustion reactions, it's crucial to consider:

  • The fuel and oxidizer involved in the reaction (commonly hydrocarbons and oxygen).

  • The products of combustion, which typically include carbon dioxide (CO2) and water (H2O).

Special Considerations

• Fractional Coefficients:

  • In balancing reactions, at times you may encounter a need to use fractional coefficients (e.g., 7/2 O2) to balance the equation.

  • However, using fractions is often discouraged in final representations of balanced equations, as chemical equations should ideally use whole number coefficients.

  • To convert fractional coefficients to whole numbers, multiply the entire equation by the denominator of the fractional coefficient.

Conclusion

• Balancing chemical equations requires careful consideration of coefficients and maintaining atom equality. Use integer coefficients for the final balanced equation and seek the simplest form.