Combustion Reaction
Molecular animation of CH₄ + 2 O₂ → CO₂ + 2 H₂O — watch molecules collide, ignite, and release heat
🔥 Combustion of Methane
Combustion is a rapid exothermic oxidation reaction between a fuel
and oxygen. For methane, the balanced equation is:
CH₄ + 2O₂ → CO₂ + 2H₂O (ΔH° = −890 kJ/mol)
Reaction occurs when molecules collide with sufficient energy ≥ the activation energy Eₐ. The Arrhenius equation governs rate: k = A · e−Eₐ/RT. Above ~600 K, thermal collisions frequently exceed Eₐ ≈ 200 kJ/mol.
Complete combustion (excess O₂): produces only CO₂ + H₂O. Incomplete combustion (insufficient O₂): additionally forms CO, soot (C), and unburned fuel. The stoichiometric ratio for air-fuel is 17.2 : 1 by mass (λ = 1).
Flame temperature: adiabatic flame temp for CH₄/air ≈ 2,230 K. The orange colour comes from incandescent soot particles (blackbody radiation), while the blue base involves CH* and C₂* radical chemiluminescence.