Combustion Reaction Calculator
Balance combustion reactions for hydrocarbons and organic compounds containing C, H, and O. Get the balanced equation and product amounts.
Number of carbon atoms in the hydrocarbon
Number of hydrogen atoms in the hydrocarbon
Number of oxygen atoms (for alcohols, ethers, etc.)
What is a combustion reaction?
Combustion is a chemical reaction where a hydrocarbon or organic compound reacts with oxygen (O₂) to produce carbon dioxide (CO₂), water (H₂O), and heat. Complete combustion requires sufficient oxygen and produces only CO₂ and H₂O.
How do you balance a combustion reaction?
For CxHyOz + O₂ → CO₂ + H₂O: 1) C balances: coefficient for CO₂ = x, 2) H balances: coefficient for H₂O = y/2, 3) O balances: count O atoms on right (2x + y/2), subtract z from compound, divide by 2 for O₂ coefficient = (2x + y/2 - z)/2. Multiply all by 2 if fractions appear.
What is the difference between complete and incomplete combustion?
Complete combustion with sufficient O₂ produces CO₂ + H₂O. Incomplete combustion (limited O₂) produces toxic CO (carbon monoxide) and/or C (soot). Example: 2CH₄ + 3O₂ → 2CO + 4H₂O (incomplete) vs CH₄ + 2O₂ → CO₂ + 2H₂O (complete).
How do you calculate heat of combustion?
Heat of combustion (ΔH°c) = Σ ΔH°f(products) - Σ ΔH°f(reactants). For methane: ΔH°c = [ΔH°f(CO₂) + 2×ΔH°f(H₂O)] - [ΔH°f(CH₄) + 2×ΔH°f(O₂)] = [-393.5 + 2(-285.8)] - [-74.8 + 0] = -890.3 kJ/mol.