Le Chatelier Shift Predictor mechanism

Model scope

The core Le Chatelier rules are chemically standard for qualitative teaching, and the honest-label warning is appropriate. Review is required because the input schema does not explicitly encode balanced stoichiometry, phases, constant-volume versus constant-pressure conditions, inert-gas behavior, or the exact meaning and units of ΔV and ΔT.

• The rule-based method is standard for qualitative equilibrium-shift prediction, but the reaction must be balanced, reversible, and annotated with physical phases and gas stoichiometry.
• Pressure/volume shifts require distinguishing a change in system volume from addition of an inert gas and require constant-temperature assumptions; the specification does not state these constraints.
• The meaning of input ΔV is ambiguous: it could mean a reactor-volume change or the reaction's stoichiometric volume change.
• Temperature predictions require a stated positive or negative temperature change and apply the ΔH sign only to the forward reaction as written.
• Concentration changes to pure solids or pure liquids do not generally shift equilibrium because their activities are approximately constant; this constraint is not stated.
• The method should explicitly handle no-op stresses, equal gas-mole counts, catalysts, and inert-gas additions, which do not shift equilibrium under specified conditions.

Units and conventions

• Concentration stresses are interpreted as molarity changes at constant temperature and volume unless otherwise specified.
• Pressure/volume stresses are interpreted for gas-phase species at constant temperature; decreasing volume means increasing pressure and increasing volume means decreasing pressure.
• Temperature changes may be supplied in K or °C differences because temperature differences have the same numerical size, but absolute temperature should be in kelvin if quantitative behavior is later added.
• ΔH is interpreted as the sign of the forward reaction as written.
• Species phases are required; pure solids and pure liquids are treated as having constant activity.
• A reaction with no stated stress magnitude is treated qualitatively: any nonzero directional change is sufficient to predict a shift.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "reaction": "N2(g) + 3 H2(g) ⇌ 2 NH3(g)",
    "delta_H_sign": "negative",
    "stress": {
      "type": "concentration",
      "action": "add",
      "species": "H2",
      "amount": "positive"
    }
  },
  "expected_outputs": {
    "shift_direction": "right, toward NH3",
    "rationale": "Adding a reactant consumes the added H2; equilibrium shifts in the direction that removes H2.",
    "stoichiometric_check": "Left side contains H2; rightward reaction consumes 3 mol H2 per 2 mol NH3 formed."
  },
  "working": "1. Identify the stressed species: H2. 2. H2 is on the left side, so the forward/right reaction consumes it. 3. Therefore the predicted shift is right, producing more NH3. 4. Stoichiometric check: 1 forward extent consumes 3 H2 and forms 2 NH3; the direction is unambiguous."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The input ΔH = 0 is numerically ordinary but lies outside the required positive/negative enthalpy classification. Without explicit validation, a rule engine could incorrectly choose a temperature-shift direction instead of rejecting or returning undefined.

Other records

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
• BOUNDARY_HAZARD_CATALOG.json