Osmotic Pressure Calculator (van't Hoff) mechanism

Model scope

The algebraic formula is correct for an ideal, sufficiently dilute solution. Review is required because the spec does not state the temperature unit, does not define whether atm, kPa, or both are returned, and does not explicitly state the dilute-solution applicability constraint. The educational and not-medical-advice labeling is appropriate.

• π = iMRT is the standard ideal-solution van't Hoff formula, but its validity is limited to sufficiently dilute solutions and an effective van't Hoff factor i; those applicability constraints are not specified.
• The temperature unit is unspecified. Temperature must be absolute temperature in kelvins, not degrees Celsius.
• The output declaration 'atm/kPa' is ambiguous: the instrument must define whether it returns one selected unit or both, with an explicit conversion and rounding policy.

Units and conventions

• Molarity M is in mol/L.
• For atm output, use R = 0.082057 L·atm·mol⁻¹·K⁻¹.
• Temperature T is in kelvins.
• For kPa output, convert using 1 atm = 101.325 kPa.
• The van't Hoff factor i is dimensionless and represents the effective number of dissolved osmotically active particles per formula unit.
• If using R = 8.314462618 J·mol⁻¹·K⁻¹ directly for kPa, concentration must instead be expressed in mol/m³; the test vectors avoid that mismatch by calculating atm first and converting to kPa.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "molarity_M": 0.15,
    "van_t_Hoff_factor_i": 2,
    "temperature_K": 298.15
  },
  "expected_outputs": {
    "osmotic_pressure_atm": 7.339588,
    "osmotic_pressure_kPa": 743.683791
  },
  "working": "π = iMRT = 2 × 0.15 mol/L × 0.082057 L·atm·mol⁻¹·K⁻¹ × 298.15 K. First, 2 × 0.15 = 0.30. Then, 0.30 × 0.082057 = 0.0246171. Then, 0.0246171 × 298.15 = 7.339588365 atm. Convert: 7.339588365 × 101.325 = 743.6837911 kPa. Rounded outputs: 7.339588 atm and 743.683791 kPa."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The extreme finite-looking inputs produce 8.2057e614 atm mathematically, which overflows plain JavaScript Number arithmetic to Infinity. The unspecified temperature unit also permits a 25 °C versus 25 K interpretation that differs by more than an order of magnitude.

Other records

Sources and evidence

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

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json