The scientific term for the sum of total energy in a thermodynamic process is enthalpy (H). Enthalpy accounts for the internal energy of a system along with the product of its pressure and volume. It is particularly useful in understanding heat transfer during chemical reactions and phase changes. Changes in enthalpy (ΔH) indicate whether a process is exothermic or endothermic, providing insight into energy efficiency and thermodynamic stability in various systems, from engines to biological reactions.