Calculating Enthalpy with Enthalpies of Formation In this article, we will cover the four most important methods, each using different data or resources:Īs you will see, different situations require different methods to get enthalpy, depending on what information you already know about your reactants and reaction. Generally, exothermic reactions are either always thermodynamically favored, or only favored at low temperatures.ĭue to the thermodynamic importance of enthalpy, chemists have developed many methods of calculating enthalpy of reaction. Generally, endothermic reactions are either not thermodynamically favored, or only favored at high temperatures.īy contrast, if a reaction’s change of enthalpy has a negative sign, chemists call the reaction “ exothermic.” Exothermic reactions instead involve reactants releasing heat into the environment. In particular, the sign of a reaction’s change of enthalpy yields important information.įor instance, if a reaction’s change of enthalpy has a positive sign, chemists call the reaction “ endothermic.” Endothermic reactions involve reactants absorbing heat from the environment. In chemistry, enthalpy has the most application when understanding the thermodynamics of a chemical reaction. Enthalpy is a “ state variable,” meaning that a system’s change in enthalpy only depends on the initial and final states of the system, rather than the particular path taken between the two states. Topics Covered in Other ArticlesĬhemists and physicists define enthalpy as the heat released by a process under constant pressure.

After reading, you will be able to calculate a reaction’s enthalpy in a variety of common situations. In this article, you will learn about the most important methods of calculating enthalpy of chemical reactions.

Enthalpy calculator with steps