Chemistry — the bookkeeping of atoms

Chemistry is accounting at the scale of atoms: nothing is created or destroyed, only rearranged, and every claim balances or it is wrong. The engine keeps the books in-domain (https://narrowhighway.com/s/54db514fbdd51c90cad455bc773f8152da3b3eb6a53119da6ddb670c9464e23b): it looked up carbon (Z=6), BALANCED methane combustion (CH4 + 2 O2 -> CO2 + 2 H2O), judged a reaction spontaneous by its free energy, classified an acid by pH, and confirmed the molar masses of water (18.015), CO2 (44.009), and salt (58.443). The null held in-domain: the unbalanced equation as written was caught and rebalanced (https://narrowhighway.com/s/3601aac39b6d8a85326b63ea32c72b7bf29f1e9c377ee7445edac90173386a4f). The honest boundary runs clean here: the RELATIONS and BALANCES seal (conservation, ΔG, stoichiometry, molar mass from atomic weights) — but which elements EXIST, their measured atomic weights, reaction rates, and bond energies are measured nature (the periodic table is discovered, not derived), and the deep 'why' of bonding is quantum mechanics. Chemistry is the bridge: physics below it (electrons, orbitals), biology above it (the genetic code is chemistry that copies itself). The whole living world runs on balanced books.