Foundation reactions

Roughly forty reactions make up the core catalogue; the subset below is the one a player meets on the road to bronze. Every thermodynamic value is sourced; every kinetic model must follow the same source-or-declared-approximation contract, which is why several of these are thermodynamically ready but not yet authored — a rate constant is only valid for a specific material, and inventing one to hit a play time is not allowed.

The cluster

Reaction	Equation	ΔH	Role
Combustion	C + O2 -> CO2	−393.5 kJ/mol	Heat, and the CO₂ that feeds Boudouard
Partial combustion	2 C + O2 -> 2 CO	−221.0 kJ/mol	The reductant, made on purpose
CO burn	2 CO + O2 -> 2 CO2	−566.0 kJ/mol	Completes combustion; consumes the hazard
Boudouard	C + CO2 ⇌ 2 CO	+172.5 kJ/mol	The keystone — hot and carbon-rich favours CO
Pyrolysis	biomass -> C + volatiles + tar	endothermic	Charcoal from wood; a surrogate model
Calcination	CaCO3 -> CaO + CO2	≈ +178.3 kJ/mol	Quicklime; equilibrium depends on CO₂ pressure
Slaking	CaO + H2O -> Ca(OH)2	−63.7 kJ/mol	Violent, exothermic — an early hazard lesson
Carbonation	Ca(OH)2 + CO2 -> CaCO3 + H2O	—	Mortar sets
Malachite roast	Cu2CO3(OH)2 -> 2 CuO + CO2 + H2O	—	The green rock becomes the oxide
Reduction	CuO + CO -> Cu + CO2	−127.0 kJ/mol	Copper
Carbothermic	2 CuO + C -> 2 Cu + CO2	—	Copper, direct with carbon
Tin reduction	SnO2 + 2 CO -> Sn + 2 CO2	—	Tin, the same way
Alloying	Cu(l) + Sn(l) -> solution	—	Bronze — a solution phase, not a compound
Tarnish	2 Cu + O2 -> 2 CuO	—	Oxidation, the slow reverse
Slag	CaO + SiO2 -> CaSiO3	—	Flux chemistry

The Boudouard equilibrium is singled out because the whole early game rests on it. Its direction must emerge from the reaction quotient, the equilibrium constant, and temperature — never a hard-coded crossover temperature stated without its state.

Implementation status

Thermodynamics are sourced for every substance in the combustion / Boudouard / calcination / slaking cluster (O₂, CO₂, CO, H₂O, CaO, Ca(OH)₂, and a self-derived graphite Shomate fit). Reaction kinetics are the blocker:

Reaction	Thermodynamics	Kinetics	Note
Combustion, partial combustion	sourced	blocked	Real rate constants are char/coal-source-specific, not one graphite constant
Boudouard	sourced	blocked	Literature Ea ranges 143–255 kJ/mol depending on the char
CO burn	sourced	partial	A primary global rate law exists (Dryer & Glassman 1973); its activation-energy units and the concentration→activity change of variables are unconfirmed
Calcination	gap	blocked	Calcite has no locatable primary Shomate fit or Cp(T) table
Slaking	sourced	blocked	Diffusion/dissolution-controlled in reality, not a simple Arrhenius step

The ReactionDefinition / ReactionCatalog authoring path itself is complete and test-covered, so adding a real reaction once its kinetics are sourced is a matter of authoring one asset.

See also

• Chemistry sources — the full provenance, cross-checks, and known gaps.
• Chemistry foundations — how the solver evaluates and couples these.
• Glossary — Boudouard, activity, Arrhenius, calcination, and the rest.