Standard Entropy of Reaction Calculator mechanism

Model scope

The summation formula is correct: ΔS°rxn = ΣνiS°i(products) − ΣνiS°i(reactants). Verdict is NEEDS_REVIEW because the specification does not define the temperature, standard-state pressure, or required phase/state metadata. The claim should not imply a uniquely determined value until those conditions are explicit. The declared data source is also not implemented because already_built is false.

No additional formula finding is recorded.

Units and conventions

• S° values must all use the same temperature, normally 298.15 K unless another temperature is explicitly selected.
• All S° values must be standard molar entropies in the same units; the reported output is J·mol⁻¹·K⁻¹ per mole of reaction as written.
• Stoichiometric coefficients are dimensionless, and fractional coefficients are permitted for a balanced equation.
• Standard states and phases must be specified consistently, typically 1 bar with explicit phases such as (s), (l), (g), or (aq).
• If input entropies are supplied in kJ·mol⁻¹·K⁻¹, they must be converted to J·mol⁻¹·K⁻¹ before reporting the output.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "balanced_equation": "CH4(g) + 2 O2(g) -> CO2(g) + 2 H2O(l)",
    "S_standard": {
      "CH4(g)": 186.3,
      "O2(g)": 205,
      "CO2(g)": 213.7,
      "H2O(l)": 69.9
    },
    "S_unit": "J mol^-1 K^-1",
    "temperature_K": 298.15
  },
  "expected_outputs": {
    "delta_S_rxn": -242.8,
    "unit": "J mol^-1 K^-1"
  },
  "working": "Products = (1 × 213.7) + (2 × 69.9) = 213.7 + 139.8 = 353.5 J mol^-1 K^-1. Reactants = (1 × 186.3) + (2 × 205.0) = 186.3 + 410.0 = 596.3 J mol^-1 K^-1. ΔS°rxn = 353.5 − 596.3 = −242.8 J mol^-1 K^-1."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The extreme-magnitude vector produces Infinity in IEEE-754 JavaScript arithmetic because the product entropy sum overflows; the calculator should reject non-finite inputs or outputs. The specification also contains no genuine multi-regime formula branch, so the branch test is necessarily a zero-crossing probe.

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
• BOUNDARY_HAZARD_CATALOG.json