Source: https://guthlabs.ai/docs/instruments/combined-combined-gas-law-calculator/

instrument / verified-clean

# Combined/Combined-Gas-Law Calculator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/combined-combined-gas-law-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/combined-combined-gas-law-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/combined-combined-gas-law-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/combined-combined-gas-law-calculator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Chemistry & Materials

**Tranche**: tranche-4

**Evidence ID**: t4-135

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The algebraic formula is correct, but the specification needs an explicit variable-selection interface, valid-domain constraints, absolute-temperature handling, and an honest applicability label. Verdict is NEEDS_REVIEW because the exact final-state input/output contract and physical assumptions are unspecified.

### Formula and scope findings

- P1V1/T1 = P2V2/T2 is the standard combined gas law for a fixed amount of an approximately ideal gas, but the specification does not state the required constant-amount and ideal-gas assumptions.

- The input description is ambiguous about which two final-state variables are supplied and how the missing final-state variable is selected or represented.

- The formula requires absolute temperature; temperatures entered in degrees Celsius must be converted to kelvins before calculation.

### Unit assumptions

- P1 and P2 must use the same pressure unit.

- V1 and V2 must use the same volume unit.

- T1 and T2 must be absolute temperatures in kelvins, or consistently converted from Celsius using T(K) = T(°C) + 273.15.

- The gas amount is constant between states and the gas is treated as ideal or sufficiently close to ideal.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The specification exposes invalid-input hazards at T=0 K and when P1*V1=0; these require rejection or an explicit undefined result. Pressure gauge-versus-absolute interpretation can also produce materially different outputs if the convention is not specified.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "P1": 1,
    "V1": 2,
    "T1": 300,
    "V2": 1.5,
    "T2": 330,
    "pressure_unit": "atm",
    "volume_unit": "L",
    "temperature_unit": "K",
    "missing": "P2"
  },
  "expected_outputs": {
    "P2": 1.4666667,
    "pressure_unit": "atm"
  },
  "working": "P1V1/T1 = P2V2/T2. Rearrange: P2 = P1V1T2/(T1V2). Substitute: P2 = (1.00 atm × 2.00 L × 330 K)/(300 K × 1.50 L) = 660/450 atm = 1.4666667 atm."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`