Combustion Reaction Calculator

Find O₂, CO₂ and H₂O for burning a hydrocarbon.

O₂ needed (mol per mol fuel) 5
CO₂ produced (mol) 3
H₂O produced (mol) 4

Formula: CₓHᵧ + (x + y/4) O₂ → x CO₂ + (y/2) H₂O

Step-by-step with your numbers:
1. Values used:
2. Carbon atoms (x) = 3
3. Hydrogen atoms (y) = 8
4.
5. O₂ needed = 5mol per mol fuel
6. CO₂ produced = 3mol
7. H₂O produced = 4mol
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Balance the complete combustion of a hydrocarbon CₓHᵧ.

How the Math Works

The Combustion Reaction Calculator uses the balanced chemical equation for complete hydrocarbon combustion: CₓHᵧ + (x + y/4) O₂ → x CO₂ + (y/2) H₂O. Here, x represents carbon atoms and y represents hydrogen atoms in the hydrocarbon. The oxygen required (x + y/4) is derived by balancing carbon and hydrogen: each carbon atom needs 1 O₂ molecule to form CO₂, while each hydrogen atom pair (H₂) requires 0.5 O₂ to form H₂O. The formula ensures stoichiometric precision for precise reactant and product calculations.

Practical Applications

To use the calculator, input the hydrocarbon's formula (e.g., CH₄ for methane, C₃H₈ for propane). The tool instantly calculates the required oxygen volume and the moles of CO₂ and H₂O produced during complete combustion. This is essential for laboratory experiments, industrial fuel efficiency optimization, and engineering applications like engine design or gas appliance safety testing, where accurate air-fuel ratios are critical.

Day-to-Day Use

This calculator simplifies everyday tasks like estimating emissions from vehicle exhaust or home heating systems, helping users understand environmental impacts. It also aids in cooking or camping scenarios—calculating gas canisters needed for a barbecue or predicting smoke production. By optimizing combustion, it supports energy conservation and reduces waste, contributing to smarter resource use in daily life.

Worked example

Propane C₃H₈ → 5 O₂, 3 CO₂, 4 H₂O.

FAQ

Incomplete combustion?

Less O₂ produces CO and soot — not covered here.