Final answer:
Calculating the enthalpy change for CH₃OH(l) + 1/2 O₂(g) → CH₄(g) requires additional data or using Hess's Law with related known reactions.
Step-by-step explanation:
The question asks to calculate the enthalpy change for the chemical reaction of methanol (CH₃OH) and oxygen (O₂) forming methane (CH₄). Hess's Law and enthalpy of formation data are needed to find the total enthalpy change of a reaction.
First, we need a balanced chemical equation for the reaction. However, the provided reaction is incomplete as it doesn't specify all the products. Assuming we aim to find the enthalpy change for the complete combustion of methanol, we could use:
CH₃OH(l) + 3/2 O₂(g) → CO₂(g) + 2 H₂O(l)
For the incomplete reaction given, CH₃OH(l) + 1/2 O₂(g) → CH₄(g), we cannot directly calculate the enthalpy change without additional data, such as enthalpies of formation or using a method akin to Hess's Law linking this reaction to others with known enthalpies.