Final answer:
The heat of the reaction for methane combustion is -890.4 kJ, signifying an exothermic process. For hydrogen production, the given K-value helps determine the direction of the reaction's progress.
Step-by-step explanation:
The heat of the reaction CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) is given as -890.4 kJ. This value indicates the amount of energy released when one mole of methane (CH₄) reacts completely with oxygen to form carbon dioxide and water. The negative sign indicates an exothermic reaction, where heat is released.
When estimating the amount of heat evolved or absorbed in a reaction, it's crucial to consider the stoichiometry of the balanced chemical equation and the molar enthalpy change. For example, if the balanced equation represents the reaction of 8 moles of a reactant and the enthalpy change is 744 kJ/mol, the total heat would be calculated as 5960 kJ for the reaction.
In the case of hydrogen production, the reaction CH₄(g)+H₂O(g)→ CO(g)+3H₂(g) with a K-value provided, allows us to calculate if a reaction mixture is at equilibrium or if it will proceed in either direction based on the reaction quotient (Q) and the equilibrium constant (K).