# Standard Enthalpy Calculator

## About Standard Enthalpy Calculator (Formula)

Standard enthalpy (also known as standard heat of reaction) is a measure of the heat energy released or absorbed during a chemical reaction under standard conditions (usually at 25°C and 1 atm pressure). It is usually expressed in Joules (J) or kilojoules (kJ).

The formula used to calculate the standard enthalpy is:

ΔH° = ΔH°(products) – ΔH°(reactants)

where ΔH° is the standard enthalpy in Joules, and ΔH°(products) and ΔH°(reactants) are the sum of the changes in enthalpy of the products and the reactants, respectively, under standard conditions.

The changes in enthalpy (ΔH) can be measured experimentally, or they can be calculated from known enthalpies of formation using Hess’s law. The standard enthalpy is calculated by taking the difference between the sum of the changes in enthalpy of the products and the sum of the changes in enthalpy of the reactants.

A standard enthalpy calculator simplifies this process by automating the calculation based on the input of the values of the sum of the changes in enthalpy of the products and the reactants.