Hess's Law Of Heat Summation
What is Hess's Law Of Heat Summation?
Hess's law states that the total enthalpy change for a chemical reaction is independent of the pathway taken and equals the sum of the enthalpy changes for any series of steps that leads from the initial reactants to the final products. This is a consequence of enthalpy being a state function. Hess's law allows the calculation of enthalpy changes for reactions that cannot be measured directly by combining thermochemical equations whose enthalpy changes are known.
Key Facts
Frequently Asked Questions
Hess's law states that the total enthalpy change for a chemical reaction is independent of the pathway taken and equals the sum of the enthalpy changes for any series of steps that leads from the initial reactants to the final products. This is a consequence of enthalpy being a state function. Hess's law allows the calculation of enthalpy changes for reactions that cannot be measured directly by combining thermochemical equations whose enthalpy changes are known.