Standard state

{
  "id": "MLC-T-CHM-011306",
  "term": "Standard state",
  "field": "Chemistry",
  "definition": "A precisely defined reference state for a substance, used to compare thermodynamic properties. For a pure substance, it is typically the pure substance at a pressure of 1 bar and a specified temperature. For a solute, it is a hypothetical solution at a concentration of 1 mol/L (or 1 mol/kg) exhibiting ideal behavior.",
  "subject": "Physical and Biophysical Chemistry",
  "see_also": [
    "dilute solution",
    "standard concentration",
    "standard pressure"
  ],
  "references": [
    "Green Book, 2nd ed., p. 53 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/standard-state/"
}