Molality Calculator

Inspectable records

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