Source: https://guthlabs.ai/docs/instruments/dalton-s-law-partial-pressure-calculator/mechanism/

instrument mechanism / verified-clean

# Dalton's Law / Partial Pressure Calculator mechanism

The inspectable method record for Dalton's Law / Partial Pressure Calculator, kept separate from implementation and qualification.

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

## Model scope

The specification is ambiguous about which input combinations are supported and omits the required conversion from component moles to mole fractions. It should explicitly define input precedence, pressure units, validation tolerances, and whether the calculator claims applicability only to ideal or sufficiently dilute gas mixtures.

- The stated formulas are standard, but the mole-input path is incomplete: it must define x_i=n_i/(sum of all component moles).

- If only component moles are supplied, a total pressure or equivalent pressure information is still required to calculate absolute partial pressures; mole fractions alone determine only relative partial pressures.

- If component pressures are supplied, the inverse formulas should be specified: P_total=sum(P_i) and x_i=P_i/P_total.

- The calculation requires the constraint sum(x_i)=1; this validation requirement is not stated.

## Units and conventions

- All pressures in a calculation must use the same unit; the output partial pressures and total pressure retain that unit.

- Moles for all components must use the same amount unit, although the unit cancels when calculating mole fractions.

- Mole fractions are dimensionless and must be nonnegative with a total of 1, subject to numerical tolerance.

- The formulas assume a nonreacting gas mixture for which Dalton's law is applicable, typically modeled as an ideal gas mixture.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "component_moles": [
      2,
      3,
      5
    ],
    "total_pressure": {
      "value": 100,
      "unit": "kPa"
    }
  },
  "expected_outputs": {
    "mole_fractions": [
      0.2,
      0.3,
      0.5
    ],
    "partial_pressures": {
      "values": [
        20,
        30,
        50
      ],
      "unit": "kPa"
    },
    "total_pressure": {
      "value": 100,
      "unit": "kPa"
    }
  },
  "working": "Sum of moles = 2 + 3 + 5 = 10 mol. Mole fractions: x1 = 2/10 = 0.2, x2 = 3/10 = 0.3, x3 = 5/10 = 0.5. Partial pressures: P1 = 0.2 x 100 = 20 kPa, P2 = 0.3 x 100 = 30 kPa, P3 = 0.5 x 100 = 50 kPa. Check: 20 + 30 + 50 = 100 kPa."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The zero-total-moles case creates 0/0 and must be rejected. The input-mode and percentage-versus-decimal probes also expose unsafe behavior if the calculator fails to validate mole-fraction ranges, normalization, or units.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/dalton-s-law-partial-pressure-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/dalton-s-law-partial-pressure-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/dalton-s-law-partial-pressure-calculator/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`