Source: https://guthlabs.ai/docs/instruments/molality-calculator/

instrument / verified-clean

# Molality Calculator

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/molality-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/molality-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/molality-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/molality-calculator/qualification/>)

## Ledger state

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

**Area**: Chemistry & Materials

**Tranche**: tranche-4

**Evidence ID**: t4-003

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The core formula is correct for mole input and kilogram solvent input. The specification needs an explicit input mode and, for mass-based solute input, a required molar-mass conversion. Until those units and requirements are defined, the catalog claim is ambiguous.

### Formula and scope findings

- The formula m = n_solute / kg_solvent is the standard molality formula only when n_solute is in moles and solvent mass is in kilograms.

- The declared input of solute mass is unsupported by the stated formula unless molar mass is also provided and the conversion n_solute = solute_mass / molar_mass is performed.

- The input unit for solvent mass is not specified; using grams directly instead of converting to kilograms produces an incorrect result.

### Unit assumptions

- n_solute is measured in mol.

- kg_solvent is the mass of solvent measured in kg, not the mass of the solution.

- If solute mass is supplied, its unit and the solute molar mass must be supplied so mass can be converted to moles.

- The output unit is mol/kg, conventionally written mol kg^-1.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The calculator has an undefined result when solvent mass is zero, should reject nonpositive solvent masses, and can produce a 1000-fold discrepancy when the solvent-mass unit is not specified.

## 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_moles": 0.5,
    "solvent_mass_kg": 2
  },
  "expected_outputs": {
    "molality_mol_per_kg": 0.25
  },
  "working": "m = n_solute / kg_solvent\nm = 0.500 mol / 2.000 kg\nm = 0.250 mol/kg"
}
````

## 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`