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Short Communication - (2023) Volume 11, Issue 2

Thermochemical Equations Involved in the Reaction's Enthalpy Change
Abdulrahman Omar*
Department of Pharmaceutical Chemistry, King Saudi University, Riyadh, Saudi Arabia
*Correspondence: Abdulrahman Omar, Department of Pharmaceutical Chemistry, King Saudi University, Riyadh, Saudi Arabia, Email:

Received: 27-Mar-2023, Manuscript No. MCA-23-21135; Editor assigned: 29-Mar-2023, Pre QC No. MCA-23-21135 (PQ); Reviewed: 14-Apr-2023, QC No. MCA-23-21135; Revised: 21-Apr-2023, Manuscript No. MCA-23-21135 (R); Published: 28-Apr-2023, DOI: 10.35248/2329-6798.23.11.411


The study of the interaction between heat and other types of energy in chemical processes is the focus of the discipline of physical chemistry known as thermochemistry. We can learn a lot about the energy shifts that take place during chemical reactions from this area of science. A crucial area of research in chemistry is thermochemistry, which has numerous real-world applications in disciplines including material science, engineering, and biochemistry. The fundamentals, laws, and applications of thermochemistry will all be covered in this article [1].

Energy is transmitted from one system to another in the form of heat. Heat will transfer from the hotter system to the cooler system when two systems come into contact. The temperature difference between the two systems and each system's heat capacity affect how much heat is transmitted [2].

A thermodynamic characteristic associated with a system's heat is called enthalpy. Enthalpy is defined as the total internal energy of a system plus the system's pressure time’s volume. The heat of reaction or enthalpy of reaction is the term used to describe the enthalpy change that occurs in a system during a chemical reaction. The difference between the enthalpies of the reactants and products determines the enthalpy change [3].

Chemical equations known as thermochemical equations involve the reaction's enthalpy change. Reactants are written on the left side of thermochemical equations, and products are written on the right side. On the right side of the equation is the enthalpy change. Kilojoules per mole (kJ/mol) are the usual units used to express the enthalpy change.

Enthalpy change has a negative sign when a reaction is exothermic, which means heat is given out during the reaction. Per mole of methane burnt in this reaction, 802 kJ of heat are generated. Chemical reactions that are advantageous from an energetic standpoint are designed using thermochemistry. This is crucial in fields like medicines where it's vital to create reactions that are effective and provide high levels of desired compounds [4].

The production of new fuels and the improvement of fuel efficiency in fuel technology both require thermochemistry.

The law of conservation of energy, the law of constant heat summation, and the law of Hess are the three essential laws that regulate thermochemistry [5].

The law of conservation of energy

Energy cannot be created or destroyed, according to the rule of conservation of energy. To put it another way, the overall energy of a system and its surrounds doesn't change. The first law of thermodynamics is another name for this rule.

The law of constant heat summation

The heat absorbed or released during a chemical reaction is independent of the process's course, according to the law of constant heat summation. In other words, whether a reaction occurs in one step or multiple stages, the enthalpy change will be the same in both cases. The law of Hess is another name for this rule.

The law of hess

The enthalpy change of a reaction is equal to the sum of the enthalpy changes of each of its component phases, according to the Hess law. The law of constant heat summation is the foundation for this rule.


Citation: Omar A (2023) Thermochemical Equations Involved in the Reaction's Enthalpy Change. Modern Chem Appl. 11:411.

Copyright: © 2023 Omar A. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.