Title: internal energy
Long Title: IUPAC Gold Book - internal energy
DOI: 10.1351/goldbook.I03103
Status: current
Index: quantity

Definition
Quantity the change in which is equal to the sum of heat, \(q\), brought to the system and work, \(w\), performed on it, \(\Delta U=q+w\). Also called thermodynamic energy.

Sources
- Green Book, 2nd ed., p. 48 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
- PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 976 (https://doi.org/10.1351/pac199668040957)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/I03103/html
- json: https://goldbook.iupac.org/terms/view/I03103/json
- xml: https://goldbook.iupac.org/terms/view/I03103/xml

Citation: Citation: 'internal energy' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.I03103
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Accessed: 2026-06-12T07:49:39+00:00