Source: https://guthlabs.ai/docs/instruments/chemistry-unit-constants-converter/mechanism/

instrument mechanism / verified-clean

# Chemistry Unit & Constants Converter mechanism

The inspectable method record for Chemistry Unit & Constants Converter, kept separate from implementation and qualification.

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

## Model scope

The core concept is valid, but the instrument cannot be verified as fully specified until its conversion-factor table, CODATA edition, citation policy, aliases, ambiguity handling, and rounding/significant-figure rules are fixed. The test vectors use explicit unit conventions and CODATA 2018 for u; changing the adopted source requires updating the corresponding expected value.

- The stated linear-conversion approach is correct, but the specification does not define the authoritative numerical conversion table, precision, or rounding policy.

- Constants lookup is underspecified: no CODATA edition or other source/version is named, so values and citations may change between releases.

- The instrument must distinguish thermochemical calorie (cal_th), international table calorie, and food calorie/kilocalorie; plain "cal" is ambiguous.

- The instrument must distinguish unified atomic mass unit (u/Da) from historical or context-specific uses of "amu" and specify the adopted value and source.

- The output requirement says constants include a source citation, but the source-citation format and required citation metadata are not specified.

## Units and conventions

- Use 1 atm = 101.325 kPa exactly; 1 bar = 100 kPa exactly; 1 atm = 760 torr exactly; for ordinary chemistry conversion, treat 1 torr and 1 mmHg as numerically equivalent, while labeling that convention explicitly.

- Use 1 cal_th = 4.184 J exactly. Do not interpret an unqualified "cal" as food Calorie/kcal.

- Use the CODATA 2018 conventional value for the unified atomic mass constant: 1 u = 1.66053906660e-27 kg; the selected CODATA edition must be displayed.

- Use the exact SI-defined Avogadro constant N_A = 6.02214076e23 mol^-1, with citation to the BIPM SI Brochure or an equivalent authoritative SI source.

- Values are interpreted as pure numbers in the stated units; output rounding and significant-figure behavior must be specified by the implementation.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "value": 1,
    "from_unit": "atm",
    "to_units": [
      "kPa",
      "mmHg",
      "torr",
      "bar"
    ]
  },
  "expected_outputs": {
    "kPa": 101.325,
    "mmHg": 760,
    "torr": 760,
    "bar": 1.01325
  },
  "working": "1 atm × (101.325 kPa/atm) = 101.325 kPa. 1 atm × (760 mmHg/atm) = 760 mmHg. 1 atm × (760 torr/atm) = 760 torr. 1 atm × (101.325 kPa/atm) × (1 bar/100 kPa) = 1.01325 bar."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

An unrecognized constant name produces an undefined lookup result and must be rejected explicitly. In addition, an unqualified pressure input cannot distinguish absolute pressure from gauge pressure without a convention warning.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/chemistry-unit-constants-converter/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/chemistry-unit-constants-converter/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/chemistry-unit-constants-converter/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-tranche6/tranche6-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`