Question

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).

Answer 1

Answer: 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 $\Delta H$ 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 $\Delta H$ 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

$\Delta H_{rxn}=+252.8kJ$

The chemical equation follows:

$2CH_3OH+252.8kJ\rightarrow 2CH_4+O_2$

Hence, the balanced chemical equation is written above.