enthalpically

Enthalpically is an adverb formed from enthalpy, the thermodynamic quantity H defined as H = U + pV for a system at pressure p with internal energy U. In context, enthalpically describes something that relates to or is determined by enthalpy, often referring to changes in enthalpy (ΔH) or properties that track enthalpy rather than other state functions.

In thermodynamics and chemistry, enthalpy changes quantify heat transfer under constant pressure. An enthalpically driven process is one whose thermodynamic driving force is primarily an enthalpy change; for example, exothermic steps that release heat may be described as enthalpically favorable, though spontaneity depends on both ΔH and entropy (ΔG = ΔH − TΔS).

The adjective enthalpic is more common; enthalpically is rarer and may appear in specialized texts, but it is understood to mean "in terms of enthalpy" or "by enthalpy changes." In practice, writers usually use enthalpy change, enthalpy-driven, or enthalpic to avoid ambiguity.

Typical applications include calorimetry, reaction energetics, and phase transitions, where enthalpy is a central quantity. When discussing spontaneous processes at constant temperature and pressure, the Gibbs free energy change, ΔG, is the decisive criterion, incorporating both enthalpy and entropy. See also: enthalpy, enthalpic, ΔH, ΔG.