ChemBench: Equation Balancer

ChemBench turns chemistry into interactive reasoning. Adjust conditions, build structures and enter calculation evidence before checking your conclusion. Compare reagents and calculate yield; predict gas quantities and partial pressures; compose reactions and calculate signed enthalpy changes. Key readings appear after the corresponding calculations pass. EIGHT SUBJECTS, 157 LEVELS Stoichiometry, solutions and acids/bases, gases and thermochemistry, redox and electrochemistry, organic structures, equilibrium, ions and precipitation, molecules and crystals. 63 levels are free; 94 require Pro. Each subject includes Intro, Core and Brainer difficulties. PRACTICE AND EXPLORE • A free daily challenge, including rotating questions drawn from Pro levels • Courses, a review queue and subject learning records; assisted and independent solves are recorded separately • Reaction Cards explain the laws using the current problem's values • 13 quick tools, including molar mass, balancing, half-reactions, equilibrium constants, ionic coexistence and solubility curves; unlimited results and non-consumable hints • Periodic trends and comparisons, 3D crystal models, packing calculations and linked concepts • iPad split layouts and handwritten scratch work; resume unfinished problems PRO — ONE-TIME PURCHASE All 157 levels, full post-solve Reaction Card derivations, quick-tool working, configurable saved experiments, and custom problem creation with offline export. Change equations, solution conditions or gas-mixture components and check a new calculation. Pro includes every answer and all Pro features. One-time purchase. No subscription. Three sample answers per category are free to view again. Unlock Pro for all remaining answers. Existing answer-pack purchases can still be restored for their original difficulty. PRIVACY AND MODELS Problems, calculations and local records work offline. No ads or analytics SDK. Each teaching model has stated limits, such as ideal gases, concentration-based acid/base calculations at 25°C and Hess reactions with specified physical states. See the in-app model notes. This is a calculation and reasoning tool; it contains no laboratory procedures and promises no exam-score gains. Support, Privacy Policy and Terms of Use are in Settings.