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

instrument implementation / implementation-contract

# Molality Calculator implementation

A source-bound implementation contract for Molality Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-003

**Effect**: Computation or source lookup only

## Input and validation requirements

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.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "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"
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/molality-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/molality-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/molality-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`