Combustion Reaction Calculator

Balanced equation will appear here.

How to Use This Combustion Calculator

Simply type the molecular formula of any hydrocarbon (like methane CH4 or propane C3H8) into the input field above. The calculator instantly balances the complete combustion reaction with oxygen (O2), showing you the correct stoichiometric coefficients for carbon dioxide (CO2) and water (H2O) products.

Understanding Hydrocarbon Combustion

Combustion reactions are fundamental in chemistry, especially when studying organic compounds and energy production. In complete combustion, hydrocarbons react with oxygen to produce carbon dioxide and water vapor, releasing significant energy in the form of heat.

As a chemistry teacher with over 10 years of classroom experience, I've found students often struggle with balancing these equations manually. This tool helps verify your work or quickly generate balanced equations for study purposes.

The Science Behind the Calculation

The general formula for complete combustion of any hydrocarbon CxHy is:

CxHy + (x + y/4)O2 → xCO2 + (y/2)H2O

Our calculator automatically applies this formula, handling fractional coefficients by finding the lowest common multiple. For example, with C2H6 (ethane):

C2H6 + 3.5O2 → 2CO2 + 3H2O

Which becomes when multiplied by 2 to eliminate fractions:

2C2H6 + 7O2 → 4CO2 + 6H2O

Practical Applications

Combustion calculations have real-world importance in:

  • Fuel efficiency analysis for automobiles and power plants
  • Environmental impact studies of CO2 emissions
  • Chemical engineering processes involving hydrocarbon fuels
  • Laboratory experiments measuring heat of combustion

Example Calculations

Methane (natural gas): CH4 + 2O2 → CO2 + 2H2O

Propane (LPG): C3H8 + 5O2 → 3CO2 + 4H2O

Octane (gasoline): 2C8H18 + 25O2 → 16CO2 + 18H2O

References & Further Reading

  • Zumdahl, S. S. & Zumdahl, S. A. (2013). Chemistry (9th ed.). Cengage Learning.
  • Atkins, P. & de Paula, J. (2014). Physical Chemistry (10th ed.). Oxford University Press.
  • EPA Technical Documentation for Greenhouse Gas Emissions Calculations

About This Tool

This combustion reaction calculator was developed by chemistry educators to help students master stoichiometry concepts. All calculations are based on fundamental chemical principles and have been verified against standard chemistry references.