Van't Hoff Factor Estimator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Chemistry & Materials

Tranche

tranche-4

Evidence ID

t4-195

Ledger rows

1

No ledger note is attached.

Review findings

The core van't Hoff ratio is standard under the stated unit and experimental-equivalence assumptions, but the specification is incomplete for i_ideal and for percent dissociation/association. Require explicit behavior selection, dissociation particle count or association aggregation number, and validation of the physical output range before labeling the result.

Formula and scope findings

• i = ΔT_measured / ΔT_calculated is valid only when both temperature changes use the same solvent, solute concentration basis, and colligative-property context; this equivalence is not stated.
• i_ideal cannot be determined from solute formula alone without explicit dissociation stoichiometry and an assumption of complete dissociation.
• For dissociation into ν particles per formula unit, the standard percent-dissociation formula is 100 × (i - 1) / (ν - 1); this formula is missing from the specification.
• Association is not defined. For aggregation into n-mers, a commonly used model is percent association = 100 × (1 - i) / (1 - 1/n), but the aggregation model and n are absent.
• The output label 'percent dissociation/association' is ambiguous unless the instrument requires the user to select dissociation versus association and provide the corresponding stoichiometry.

Unit assumptions

• ΔT_measured and ΔT_calculated must both be temperature differences, not absolute temperatures, and must use the same units.
• Temperature differences have the same numerical magnitude in degrees Celsius and kelvin: 1 °C difference = 1 K difference.
• ΔT_calculated is assumed to be the nonelectrolyte value for the same solvent, solute concentration, and relevant colligative property.
• For dissociation vectors, i_ideal equals the number of dissolved particles produced per formula unit under complete dissociation.
• Percent dissociation assumes ν > 1 and uses 100 × (i - 1) / (ν - 1).
• The association example assumes reversible dimerization only, with n = 2 and percent association = 100 × (1 - i) / (1 - 1/n).

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The zero expected nonelectrolyte temperature difference creates an undefined division, and an undocumented signed-versus-magnitude ΔT convention can produce a negative van't Hoff factor and nonsensical negative dissociation. The branch probe also requires explicit selection between association and dissociation formulas.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "solute": "NaCl",
    "behavior": "dissociation",
    "measured_delta_T": "1.50 K",
    "expected_nonelectrolyte_delta_T": "1.00 K",
    "ions_per_formula_unit": 2
  },
  "expected_outputs": {
    "i": 1.5,
    "i_ideal": 2,
    "percent_dissociation": 50,
    "percent_association": null
  },
  "working": "i = 1.50 / 1.00 = 1.50. For NaCl, ν = 2, so i_ideal = 2. Percent dissociation = 100 × (1.50 - 1) / (2 - 1) = 100 × 0.50 / 1 = 50%."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json