Chemistry is accounting for atoms and charge — done exactly.

Beginning chemistry where the verification system is the product. A build-time engine balances every equation, conserves charge, sources every empirical rule, and refuses to publish a claim it cannot prove. Nothing here is asserted — it is checked, and the check is shown.

The one object underneath every topic — the species ledger over reaction extent:

n_i = n_{i,0} + \nu_i\,\xi

Balancing, stoichiometry, limiting reagents, ICE tables, kinetics, thermochemistry, electrochemistry — all are views of the same conserved, changing system. Track each species’ amount as the reaction runs a distance ξ, and the limiting reagent, the leftovers, and the product mass all fall out of one ledger.

\begin{aligned} \text{Ca}^{2+} + \text{CO}_3^{2-} &\rightarrow \text{CaCO}_3(s) \\ \xi_{\max} &= \min_i \frac{n_{i,0}}{\lvert\nu_i\rvert} \quad\text{(a reactant hits zero — it limits)} \end{aligned}

Three honesty badges — every claim carries one

Machine-checked

The engine derived and verified it — atom balance, charge balance, units, extent. The proof is shown.

Data / rule-sourced

From a cited dataset or rule (atomic weights, ion charges, solubility rules) — source and version revealed, never dressed up as a theorem.

Model-assumed

An author-stated idealization (complete dissociation, additive volumes) — disclosed, not discharged.

Open the lessons →How it is verified

New here? Start at the top.

The lessons are ordered as a course — six tiers from the mole up through electrochemistry — so work top to bottom. Build fluency in the Gym, where the foundation drills (converting amounts, naming compounds, balancing) live and every problem is generated fresh and machine-checked. And the Valence Table is an interactive periodic table with four modes — trends, bonding, ion charges, and 182 machine-verified salt names.