When the enthalpy of the reaction is provided, it is always in the context of moles; i. e., δhrxn=+252.8 kj when two moles of ch3oh (methanol) decomposes into two moles of ch4 and one mole of o2. therefore, you can state that 252.8 kj is transferred when 2 mol ch3oh decompose or when 1 mol o2 is formed (based on the coefficients of the balanced equation).

The balanced chemical equation is written below.

Explanation:

There are 2 types of chemical reaction classified on the basis of heat change:

Endothermic reactions : They are the reactions in which energy of products is more than the energy of the reactants. For these reactions, energy is absorbed by the system. The comes out to be positive and is written on the reactants side.Exothermic reactions: They are the reactions in which energy of reactants is more than the energy of the products. For these reactions, energy is released by the system. The comes out to be negative and is written on the product side.

We are given:

Moles of methanol = 2 moles

Moles of methane = 2 moles

Moles of oxygen gas = 1 mole

The chemical equation follows:

Hence, the balanced chemical equation is written above.

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