Combustion Reaction Calculator

Combustion Reaction Calculator

What is a Combustion Reaction?

A combustion reaction is a high-temperature exothermic chemical reaction that involves a fuel and an oxidant, usually atmospheric oxygen. The most common examples involve the burning of hydrocarbons (compounds made of carbon and hydrogen, sometimes with oxygen).

A complete combustion reaction, which this calculator solves, assumes there is enough oxygen to react with the fuel completely. For a hydrocarbon, the only products are:

  • Carbon Dioxide (CO₂)
  • Water (H₂O)

The general unbalanced form is: CₓHᵧOₙ + O₂ ⟶ CO₂ + H₂O

Frequently Asked Questions

What's the difference between complete and incomplete combustion?

Complete combustion (which this calculator assumes) happens when there is a plentiful supply of oxygen. It releases the maximum amount of energy and produces only CO₂ and H₂O.

Incomplete combustion happens when the oxygen supply is limited. It releases less energy and produces other, more harmful products, including Carbon Monoxide (CO) (a toxic gas) and/or Carbon (C) (soot).

Why are combustion reactions important?

Combustion is one of the most important chemical reactions to humanity. It's the basis for:
• Energy Generation: Burning fossil fuels like natural gas (methane, CH₄), gasoline (octane, C₈H₁₈), and coal to produce electricity and heat.
• Transportation: Powering internal combustion engines in cars, planes, and ships.
• Daily Life: Cooking with a gas stove or heating a home with a furnace.

Why do you sometimes need to double all the coefficients?

This happens when the balancing process requires a fractional coefficient for oxygen (e.g., 3.5 O₂). Since you can't have half a molecule in a balanced equation, we multiply all coefficients in the entire equation by 2 to get the simplest whole-number ratio. For example, C₂H₆ + 3.5 O₂ ⟶ 2 CO₂ + 3 H₂O becomes 2 C₂H₆ + 7 O₂ ⟶ 4 CO₂ + 6 H₂O.