Source: https://guthlabs.ai/docs/instruments/percent-composition-calculator/implementation/

instrument implementation / implementation-contract

# Percent Composition Calculator implementation

A source-bound implementation contract for Percent Composition 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**: t2-003

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-count input H0 produces an undefined 0/0 calculation unless explicitly rejected. Parenthesis handling and hydrate-dot interpretation also create materially different results if parser conventions are not enforced.

## 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": {
    "formula": "H2O",
    "atomic_weights": {
      "H": 1.008,
      "O": 15.999
    }
  },
  "expected_outputs": {
    "per_element_percent": {
      "H": 11.190674,
      "O": 88.809326
    },
    "total_percent": 100
  },
  "working": "M = (2×1.008) + (1×15.999) = 2.016 + 15.999 = 18.015 g/mol. H% = (2×1.008 ÷ 18.015)×100 = (2.016 ÷ 18.015)×100 = 11.190674%. O% = (1×15.999 ÷ 18.015)×100 = 88.809326%. Check: 11.190674 + 88.809326 = 100.000000%."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/percent-composition-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/percent-composition-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/percent-composition-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-tranche2/tranche2-results.json`