Source: https://guthlabs.ai/docs/instruments/specific-heat-ratio-cp-cv-lookup/implementation/

instrument implementation / implementation-contract

# Specific Heat Ratio (γ) / Cp,Cv Lookup implementation

A source-bound implementation contract for Specific Heat Ratio (γ) / Cp,Cv Lookup; 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**: t7-108

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not define table-validity limits, a temperature-branch threshold, or the Cp/Cv unit basis. An implementation could accept 0 K or extreme temperatures, silently extrapolate, reuse reference values across a temperature branch, or report mass-specific values with molar units.

## 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": {
    "gas": "dry air",
    "temperature_K": 300
  },
  "expected_outputs": {
    "Cp_J_per_kg_K": 1005,
    "Cv_J_per_kg_K": 718,
    "gamma": 1.3997214485,
    "R_J_per_kg_K": 287
  },
  "reference_data": {
    "table_row": {
      "temperature_K": 300,
      "Cp_J_per_kg_K": 1005,
      "Cv_J_per_kg_K": 718,
      "R_J_per_kg_K": 287,
      "source_convention": "Widely tabulated standard ideal-dry-air value; textbook/CRC convention"
    }
  },
  "working": "γ = Cp/Cv = 1005/718 = 1.3997214485. R = Cp − Cv = 1005 − 718 = 287 J/(kg·K). The R = 287 J/(kg·K) dry-air value is the standard memorized reference value."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/specific-heat-ratio-cp-cv-lookup/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/specific-heat-ratio-cp-cv-lookup/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/specific-heat-ratio-cp-cv-lookup/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-tranche7/tranche7-results.json`