The field of chemistry known as thermodynamics deals with heat as well as system energy and changes in system energy.
The enthalpy of a system is equal to the amount of heat absorbed or emitted by the system at constant pressure.
It is similar to the internal energy of a system, which is the total energy of the system.
The change in enthalpy is comparable to the system's internal energy change. It is represented by the letter .
Any energy that is released or absorbed by the system will cause an equal change in internal energy. It has been noted that only constant volume and pressure allow for this type of reaction.
Internal energy is, therefore, equal to the sum of all completed work as well as the volume pressure product. The definition and derivation of enthalpy are shown as follows: .
As a result, we can now express it as follows if we want to describe changes in energy levels or enthalpy:
You should take note of the following two things with this:
At constant volume, The internal energy of a system is equal to the heat released or absorbed during a reaction.
At constant pressure, The system's enthalpy is equal to the heat produced or absorbed during a reaction.