Question

What are the applications of Hess’s law of constant heat summation?

Answer 1

Hess’s law explains the change of enthalpy of the chemical reaction is equal to the same in any case of the path by which the reaction occurs. Hess's law defines the increase in the chemical reaction. Which means, at constant pressure, the reaction heat is independent of the process between the initial stage and the final stage. And it is an important law. Because, there is an inequality for the conservation of energy chemically and it demonstrates the law of thermodynamics.

Complete answer:
We need to know that Hess's law simplifies that, the change in energy in overall chemical reaction is equal to the sum of change in energy present in the individual reactions which comprise it. Hess's law is a variation of the law of conservation of energy and first law of thermodynamics.
The Hess’s law has some applications, which is,
The law helps to determine the enthalpy of formation of the compounds which cannot be found experimentally.
Hess's law is to find out the enthalpy of allotropic transformation like carbon compounds, such as graphite and diamond.
And this law is helps to determine the enthalpy of hydration

Note:
We have to remember that Hess's law is very useful to determine the heat of many reactions which do not occur directly. It is very helpful to calculate the heat, especially for the slow reaction. And Hess's law is useful to determine the heat of neutralization and heat of formation, heat of combustion etc. And it is used to calculate the enthalpies of reactants as well as the products, and bond enthalpy, lattice energy etc.