Source: https://guthlabs.ai/docs/instruments/osmotic-pressure-calculator-van-t-hoff/

instrument / verified-clean

# Osmotic Pressure Calculator (van't Hoff)

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

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/osmotic-pressure-calculator-van-t-hoff/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/osmotic-pressure-calculator-van-t-hoff/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/osmotic-pressure-calculator-van-t-hoff/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/osmotic-pressure-calculator-van-t-hoff/qualification/>)

## Ledger state

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

**Area**: Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

**Tranche**: tranche-5

**Evidence ID**: t5-193

**Ledger rows**: 1

No ledger note is attached.

## Review findings

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.

### Formula and scope findings

- 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.

### Unit assumptions

- 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.

## Boundary hardening

**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.

## 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": {
    "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."
}
````

## 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-tranche5/tranche5-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`