Source: https://guthlabs.ai/docs/instruments/integrated-rate-law-solver/implementation/

instrument implementation / implementation-contract

# Integrated Rate Law Solver implementation

A source-bound implementation contract for Integrated Rate Law Solver; 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**: t6-119

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-concentration second-order request causes division by zero and must not produce an ordinary numeric time. Negative-k handling is also underspecified: literal arithmetic gives growth, while the conventional rate-constant interpretation should reject the input.

## 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": {
    "order": 0,
    "k": 0.0025,
    "k_units": "M/s",
    "A0": 0.1,
    "A0_units": "M",
    "t": 20,
    "t_units": "s",
    "solve_for": "A"
  },
  "expected_outputs": {
    "A": 0.05,
    "A_units": "M",
    "sampled_points": [
      {
        "t": 0,
        "A": 0.1
      },
      {
        "t": 20,
        "A": 0.05
      },
      {
        "t": 40,
        "A": 0
      }
    ],
    "curve_features": {
      "slope": "-0.0025 M/s",
      "zero_concentration_time": 40,
      "zero_concentration_time_units": "s",
      "valid_nonnegative_domain": "0 <= t <= 40 s"
    }
  },
  "working": "Zero-order law: A=A0-kt. At t=20 s, kt=(0.0025 M/s)(20 s)=0.0500 M. Therefore A=0.100 M-0.0500 M=0.0500 M. Boundary check: at t=A0/k=(0.100 M)/(0.0025 M/s)=40.0 s, A=0; for t>40.0 s the algebraic result is negative and is not a physical concentration."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/integrated-rate-law-solver/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/integrated-rate-law-solver/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/integrated-rate-law-solver/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`