Reaktionsenergie vs. Reaktionsenthalpie

Attribute	Reaktionsenergie	Reaktionsenthalpie
Definition	Die Energie, die bei einer chemischen Reaktion freigesetzt oder aufgenommen wird.	Die Energieänderung, die bei einer chemischen Reaktion unter konstantem Druck stattfindet.
Vorzeichen	Kann positiv oder negativ sein, je nachdem ob Energie freigesetzt oder aufgenommen wird.	Kann positiv oder negativ sein, je nachdem ob die Reaktion exotherm oder endotherm ist.
Einheit	Joule (J) oder Kilokalorie (kcal)	Joule (J) oder Kilokalorie (kcal)
Berechnung	Reaktionsenergie = Energie der Produkte - Energie der Edukte	Reaktionsenthalpie = Enthalpie der Produkte - Enthalpie der Edukte

Definition

Reaktionsenergie and Reaktionsenthalpie are two important concepts in chemistry that are often used to describe the energy changes that occur during a chemical reaction. Reaktionsenergie, also known as reaction energy, refers to the total energy change that takes place during a chemical reaction. This includes both the energy that is absorbed and released during the reaction. On the other hand, Reaktionsenthalpie, or reaction enthalpy, specifically refers to the heat energy change that occurs during a reaction at constant pressure.

Units

One key difference between Reaktionsenergie and Reaktionsenthalpie is the units in which they are measured. Reaktionsenergie is typically measured in joules (J) or kilojoules (kJ), which are units of energy. On the other hand, Reaktionsenthalpie is usually measured in kilojoules per mole (kJ/mol), which represents the heat energy change per mole of reactant or product in the reaction.

Calculation

When it comes to calculating Reaktionsenergie and Reaktionsenthalpie, the methods differ slightly. Reaktionsenergie can be calculated by subtracting the total energy of the reactants from the total energy of the products in a chemical reaction. This difference represents the overall energy change that occurs during the reaction. Reaktionsenthalpie, on the other hand, is calculated using the enthalpy of formation values for the reactants and products in the reaction. By subtracting the sum of the enthalpies of the reactants from the sum of the enthalpies of the products, the enthalpy change of the reaction can be determined.

Sign Convention

Another important distinction between Reaktionsenergie and Reaktionsenthalpie is the sign convention used to represent energy changes. In the case of Reaktionsenergie, a negative value indicates that energy is released during the reaction, while a positive value indicates that energy is absorbed. On the other hand, Reaktionsenthalpie follows a different convention. A negative value for Reaktionsenthalpie signifies that the reaction is exothermic, meaning that heat is released. Conversely, a positive value indicates an endothermic reaction, where heat is absorbed.

Application

Both Reaktionsenergie and Reaktionsenthalpie play crucial roles in understanding and predicting the behavior of chemical reactions. Reaktionsenergie provides insight into the overall energy changes that occur during a reaction, which can help determine whether a reaction is energetically favorable or not. Reaktionsenthalpie, on the other hand, is particularly useful in determining the heat effects of a reaction, which is important for various industrial processes and applications.

Relationship

While Reaktionsenergie and Reaktionsenthalpie are related concepts, they are not interchangeable. Reaktionsenergie encompasses all forms of energy changes in a reaction, including heat, work, and potential energy. Reaktionsenthalpie, on the other hand, specifically focuses on the heat energy change that accompanies a reaction. It is important to consider both concepts together to gain a comprehensive understanding of the energy changes that occur during chemical reactions.