Standard Enthalpy of Reaction (ΔH°f) Calculator 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

t4-219

Effect

Computation or source lookup only

Input and validation requirements

The extreme user-supplied formation enthalpies cause the plain JavaScript arithmetic result to overflow to +Infinity. The specification does not state finite-input validation or non-finite-output rejection. A secondary hazard is that the formula has no genuine branch switch, despite the branch-switch test requirement.

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": {
    "balanced_equation": "CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l)",
    "reactants": [
      {
        "species": "CH4(g)",
        "coefficient": 1,
        "delta_Hf_kJ_per_mol": -74.85
      },
      {
        "species": "O2(g)",
        "coefficient": 2,
        "delta_Hf_kJ_per_mol": 0
      }
    ],
    "products": [
      {
        "species": "CO2(g)",
        "coefficient": 1,
        "delta_Hf_kJ_per_mol": -393.51
      },
      {
        "species": "H2O(l)",
        "coefficient": 2,
        "delta_Hf_kJ_per_mol": -285.83
      }
    ]
  },
  "expected_outputs": {
    "delta_H_rxn_kJ_per_mol_reaction": -890.32
  },
  "working": "Products = 1×(−393.51) + 2×(−285.83) = −393.51 − 571.66 = −965.17 kJ. Reactants = 1×(−74.85) + 2×0 = −74.85 kJ. ΔH°rxn = −965.17 − (−74.85) = −965.17 + 74.85 = −890.32 kJ per mol reaction."
}

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-tranche4/tranche4-results.json