Enthalpy and internal energy.

[Meghna2A]

We know that enthaply is the study of heat released/absorbed in a chemical reaction and the physical changes related to it. But also that all objects in the universe have a preexisting energy called internal energy. Is there any correlation between enthalpy and internal energy?

[Lisa Tang 1C]

Enthalpy H is related to internal energy of a system. When a system and its surroundings do no work, the heat given off or absorbed by the system is equal to the change in the internal energy of the system.
Also, in general, H = U + P*V, where U is internal energy; P, pressure; and V, volume of the system. So, there is a relationship between enthalpy and internal energy.