Helium dead-space

{
  "id": "MLC-T-CHM-005164",
  "term": "Helium dead-space",
  "field": "Chemistry",
  "definition": "The volume within an apparatus that is not occupied by the sample and is accessible to helium gas during a measurement, but does not contribute to the sample's measured volume. This volume must be accurately determined and accounted for in experiments, such as gas pycnometry, to obtain precise sample density or volume measurements. It represents the void space in the system.",
  "subject": "Physical and Biophysical Chemistry",
  "see_also": [
    "Gibbs surface",
    "adsorption"
  ],
  "references": [
    "PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 595 (https://doi.org/10.1351/pac197231040577)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/helium-dead-space/"
}