What is the Difference Between Thermochemical Equation and Chemical Equation?

06/04/2025 • Matheus Moraes

The main difference between a thermochemical equation and a chemical equation lies in the inclusion of the enthalpy change of the reaction in the thermochemical equation. Here is a comparison of the two types of equations:

Chemical Equation:

  • Shows the starting compound, reactants, and final products separated by an arrow.
  • Does not usually indicate the enthalpy change of the reaction.

Thermochemical Equation:

  • A balanced stoichiometric chemical reaction that includes the enthalpy change.
  • Indicates the enthalpy change of the reaction, denoted by ΔH.

In summary, a thermochemical equation is a chemical equation that additionally includes the enthalpy change of the reaction, providing information about the heat energy involved in the process. A chemical equation, on the other hand, only shows the reactants and products without specifying the enthalpy change.

Comparative Table: Thermochemical Equation vs Chemical Equation

Here is a table comparing thermochemical equations and chemical equations:

Feature Thermochemical Equation Chemical Equation
Definition A balanced stoichiometric chemical reaction that includes the enthalpy change. An equation showing the starting compound, reactants, and final products separated by an arrow.
Enthalpy Change Indicates the enthalpy change of reactions, denoted by ΔH. Does not explicitly show the enthalpy change.
Format A + B → C; ΔH = (±) #, where A and B are reactants, C is the final product, and (±) # is the positive or negative numerical values for enthalpy change. Reactants → Products, where the starting compound and reactants are on the left side, and the final products are on the right side, separated by an arrow.
Application Used to calculate the heat absorbed or released during a chemical reaction. Used to represent the reactants and products of a chemical reaction.

The key difference between thermochemical equations and chemical equations is that thermochemical equations always indicate the enthalpy change of reactions, while chemical equations do not explicitly show the enthalpy change.

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