Source: https://guthlabs.ai/docs/instruments/standard-cell-potential-e-cell-calculator/implementation/

instrument implementation / implementation-contract

# Standard Cell Potential (E°cell) Calculator implementation

A source-bound implementation contract for Standard Cell Potential (E°cell) 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**: t6-102

**Effect**: Computation or source lookup only

## Input and validation requirements

The plain-JavaScript arithmetic can overflow for extreme entered potentials, producing Infinity and -Infinity rather than a finite result. The convention probe also shows that reversing cathode/anode interpretation reverses both E°cell and spontaneity.

## 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": {
    "cathode_half_reaction": "Cu²⁺ + 2e⁻ → Cu(s)",
    "E°cathode_V": 0.34,
    "anode_half_reaction": "Zn²⁺ + 2e⁻ → Zn(s)",
    "E°anode_V": -0.76,
    "n": 2,
    "F_C_per_mol_e": 96485
  },
  "expected_outputs": {
    "E°cell_V": 1.1,
    "spontaneity": "spontaneous",
    "ΔG°_J_per_mol": -212267,
    "ΔG°_kJ_per_mol": -212.267
  },
  "working": "E°cell = 0.34 − (−0.76) = 0.34 + 0.76 = 1.10 V. ΔG° = −nFE°cell = −(2)(96485 C mol⁻¹)(1.10 V) = −212267 C·V mol⁻¹ = −212267 J mol⁻¹ = −212.267 kJ mol⁻¹. Since E°cell > 0, the written cell reaction is spontaneous under standard conditions."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/standard-cell-potential-e-cell-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/standard-cell-potential-e-cell-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/standard-cell-potential-e-cell-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-tranche6/tranche6-results.json`