Enthalpy change is a state function defined solely by the initial and final states of a system, meaning its overall change is independent of the reaction pathway (whether occurring in a single step or multiple steps, a principle formalized as Hess's law); this is a foundational principle of thermodynamics that does not require citation.
The claim states that enthalpy change is a state function and independent of the reaction pathway. This is a fundamental, axiomatic law of thermodynamics (often taught as Hess's law or a core property of state functions) that is trivially true by definition and everyday chemical observation. Per the instructions, statements that are trivially true by definition or direct observation are classified as COMMON_KNOWLEDGE, requiring no citation or evidence matching, and leave the index lists empty.