Final answer:
The reaction CH₄ + 2O₂ = CO₂ + 2H₂O is a combustion reaction, where methane combusts with oxygen to produce carbon dioxide and water.
Step-by-step explanation:
The reaction CH₄ + 2O₂ = CO₂ + 2H₂O is an example of a combustion reaction. This is because the methane (CH₄) is reacting with oxygen (O₂), which are the reactants, to produce carbon dioxide (CO₂) and water (H₂O), the products. Combustion reactions are characterized by a substance combining with oxygen gas, often releasing energy in the form of heat and light.
A decomposition reaction is where a single compound breaks down into two or more elements or new compounds, such as H₂CO₃ decomposing into H₂O and CO₂ upon heating. A combination reaction is the reverse, where two or more elements or compounds combine to form a single compound, which is not the case in the given reaction.
Therefore, CH₄ + 2O₂ = CO₂ + 2H₂O is not a combination reaction because it does not result in a single product, nor is it a decomposition reaction because it does not start with a single reactant breaking down into multiple products.