Percent Solution / Concentration-Unit Converter implementation

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

t3-015

Effect

Computation or source lookup only

Input and validation requirements

The specification exposes two concrete failure hazards: 100% w/w causes division by zero in molality, and several requested conversions, especially %v/v, are underdetermined without solute density. ppm-to-molarity also changes from an approximate dilute-aqueous branch to a density-corrected branch when density is supplied.

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_mass_g": 5,
    "solution_volume_mL": 100,
    "solute_molar_mass_g_per_mol": 58.44,
    "medium": "dilute aqueous"
  },
  "expected_outputs": {
    "percent_w_v": 5,
    "solute_mass_g_per_L": 50,
    "molarity_mol_per_L": 0.855578
  },
  "working": "%w/v=(5 g/100 mL)×100=5% w/v. 100 mL=0.100 L, so 5 g/0.100 L=50 g/L. Molarity=50 g/L ÷ 58.44 g/mol=0.855578 mol/L. Under the dilute-aqueous assumption, ppm=50 g/L×1000 mg/g=50000 mg/L=50000 ppm."
}

Other records

Sources and evidence

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

• VERIFIED_LEDGER.json
• evidence-tranche3/tranche3-results.json