Final answer:
The enthalpy of combustion of methane is -890.4 kJ, indicating an exothermic reaction that releases heat.
Step-by-step explanation:
The enthalpy of combustion of methane is -890.4 kJ. This value indicates that the reaction is exothermic, implying that heat is released during the combustion of methane. In a balanced thermochemical equation, this is shown as either a negative sign in front of the enthalpy value or the heat quantity written on the product side of the equation. Therefore, when 1 mol of methane (CH4) combusts with oxygen (O2), it produces carbon dioxide (CO2) and water (H2O), releasing 890.4 kJ of heat in the process.