Answer:
The total heat content of the system.
Step-by-step explanation:
- Enthalpy is a thermodynamic quantity equivalent to the total heat content of a system.
- Enthalpy is equal to the system's internal energy plus the product of its pressure and volume.
- In a system enclosed so as to prevent matter transfer, for processes at constant pressure, the heat absorbed or released equals the change in enthalpy.
So, the right choice is: The total heat content of the system.