chemical reaction
Let an agent reason about a reaction through its equation, conditions, rate, energy and hazards, and never give instructions that make a dangerous reaction easier to perform.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent reason about a reaction through its equation, conditions, rate, energy and hazards, and never give instructions that make a dangerous reaction easier to perform.
A process in which substances, the reactants, are transformed into different substances, the products, by breaking and forming chemical bonds, while elements are conserved.
What it is for: Making new substances, releasing or storing energy, and explaining change in matter.
It can be write and balance its equation; control it, through temperature, pressure, concentration and catalysts; measure its rate, yield and energy change; scale it up, which changes the hazards.
Distinguishing features
New substances form, unlike physical changes such as melting
Atoms are conserved; nuclear reactions are a different category
Described by a balanced equation with stoichiometry
Rate and equilibrium are separate questions
What it looks like
Signs include colour change, gas bubbles, a precipitate, heat or light, or a change in smell; many reactions show no visible sign.
Physical character
enthalpy of reaction: -several thousand to +several hundred kJ/mol - negative is exothermic
activation energy: 10-300 kJ/mol - governs how rate depends on temperature
How it is recognised
A new substance appears, seen as a precipitate, gas or colour change
Temperature changes without heating or cooling from outside
Visible signs are not conclusive; analysis confirms the products
Related models
transforms - reactants and products are substance models
is described by - the balanced equation is its formal record
is controlled by - catalysts change rate without being consumed
is confused with - no new substance forms in a physical change
In practice
Families and kinds
by mechanism: synthesis, decomposition, substitution, redox, acid-base, precipitation, combustion
by energy: exothermic, endothermic
by phase: homogeneous, heterogeneous
by catalysis: catalysed, enzymatic, uncatalysed
Identifiers
Rhea ID numeric curated biochemical reactions
RInChI reaction InChI string standard reaction identifier
Standards and regulation
IUPAC recommendations on nomenclature and kinetics
Process safety regulations such as Seveso III in the EU and OSHA PSM in the US
GHS labelling for the substances involved
Failure modes and hazards
Runaway exothermic reactions, which cause fires and explosions
Toxic or flammable products and by-products
Incompatible reactants mixed by mistake
Scale-up that changes heat removal and hazards
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Equation and stoichiometry What reacts and what forms.
The balanced equation is the minimum record of a reaction.
Equation
Reactants and products.
Balanced equation
The balanced equation and states.
- What is the balanced equation, with states of matter? definition
- Which side products or by-products form? definition
Yield
Theoretical and actual yield.
Yield data
The yield obtained and expected.
- What is the theoretical and actual yield? measurement
- What limits the yield? definition
Conditions and kinetics How fast and under what conditions.
Conditions and rate decide whether a reaction is useful or dangerous.
Conditions
Temperature, pressure, solvent and catalyst.
Reaction conditions
The conditions used.
- Under what conditions does the reaction proceed? definition
- What catalyst, if any, is involved? definition
Rate
Rate law and activation energy.
Kinetic data
The rate law and parameters.
- What is the rate law, and how was it determined? measurement
- How does the rate change with temperature? measurement
Energy and equilibrium Heat and extent.
Energy change is both a resource and the main hazard.
Energy change
Enthalpy and heat release.
Thermochemistry
The enthalpy change and heat release rate.
- What is the enthalpy change? measurement
- How fast is heat released, and can it be removed? boundary
Equilibrium
Extent and reversibility.
Equilibrium data
The equilibrium constant and position.
- Is the reaction reversible, and what is its equilibrium constant? measurement
- How can the equilibrium be shifted? definition
Safety Hazards and limits.
Reaction hazards come from energy, products and incompatibility; the model must carry them and refuse unsafe help.
Hazards
Runaway, toxic products and incompatibility.
Hazard assessment
The hazards and their controls.
- Which hazards does this reaction present? boundary
- What controls are required at this scale? action
Limits on assistance
What an agent must not help with.
Assistance limits
Requests that must be declined.
- Would giving procedural detail here make harm easier? boundary
- What safe, general information can be given instead? action
What the second pass must settle
- Should reaction classes and specific reactions be separate entries?
- How should reaction hazards be represented so agents decline unsafe requests consistently?
- Which identifier should be preferred for reactions?