Answer:
A. Enthalpy of the reaction
Explanation:
A Thermochemical equation is a balanced stoichiometric chemical equation that indicates the absorption or release of heat in addition to the reactants and products involved in the chemical reaction. The amount of energy available for conversion into heat is represented by ΔH, a this term which stands for the enthalpy change, ΔH.
The Enthalpy of Reaction or Heat of Reaction is the amount of energy in the form of heat transferred during a chemical reaction that occurs at a constant pressure. It is useful for calculating the amount of energy per mole either released or produced in a reaction, therefore is unit is kJ/mol.
In a reaction where energy is absorbed by the reactants during the formation of products, ΔH is positive. On the other hand, in a reaction where energy is released by the reactants during the formation of products, ΔH is negative.
The enthalpy change, ΔH of reactions are determined experimentally under standard conditions of 1 atm and 25 °C (298.15K). Enthalpy can be measured experimentally through the use of a calorimeter. A calorimeter is an isolated system which has a constant pressure and in which heat loss to the surroundings is minimal.
