ChemReaX™ is a free web app for modeling and simulating basic chemical reactions. The software is intended for chemistry students and their teachers at the undergraduate and high school (AP/IB) levels. The ChemReaX simluation platform makes it easy to create sophisticated virtual labs in general chemistry and physical chemistry courses.

ChemReaX can be used to experiment with chemical thermodynamics, reaction equilibria, kinetics, and acid-base titration. It includes thermodynamic properties for over 1200 chemical species, allowing users to construct a virtually unlimited variety of chemical reactions. Or users can choose from over 80 predefined reactions. ChemReaX simulates a given reaction from initial conditions to a final equilibrium state, and accurately models the effects of concentrations, temperature and pressure. It comes with a detailed user guide, tutorials and several ready-to-use virtual lab exercises.

ChemReax is listed in the National Science Digital Library , MERLOT, EdSurge and LearnPlatform databases as an online chemistry education tool, and is also available through the LibreTexts open-access textbook project.


  • Allows users to construct a virtually unlimited variety of chemical reactions using the 1200+ species in the internal database, and automatically verifies the validity of the equations and/or automatically balances the equations. It also comes with over 80 pre-defined reactions that can be quickly selected under 10 different categories.
  • Simulates a given reaction from the initial conditions until it reaches a final equilibrium state using an event-driven simulation algorithm, and accurately generates the final concentrations of all reaction components based on initial concentrations (or partial pressures) and temperature.
  • Evaluates the effects of pressure changes at equilibrium and produces the pressure-adjusted final compositions of products and reactants.
  • Simulates reaction kinetics utilizing a reaction-rate model (with user-defined parameters) based on a time-driven simulation algorithm, and displays the reactant/product compositions graphically as a function of time.
  • Simulates acid-base titrations utilizing the same underlying simulation technology used for general reactions.
  • Puts a powerful modeling and simulation capability in the hands of chemistry students and teachers. It is not an animation tool, but a real simulation tool -- similar to tools used in industry -- that can help with serious scientific study and inquiry and enable an investigative/experimental approach to learning chemistry.
  • Provides the largest free online database of chemical thermodynamic properties as a function of temperature.

Accessing and using the tool:

  • ChemReaX is web-based and hosted on the cloud. There is nothing to install on the user's computer and any web browser will do for accessing the tool. The tool can be accessed at .
  • Tutorial articles are available to demonstrate how ChemReaX can be used as a virtual chemistry lab in general chemistry and physical chemistry courses in undergraduate and high-school AP/IB programs: . Topics covered include: reaction equilibria, entropy, chemical kinetics, acid-base titrations, and modeling solids/liquids/solutes in chemical thermodynamics.
  • ChemReaX-based virtual chemistry lab exercises and assignments are easy to create. Several ready-to-use virtual lab exercises are available at Topics covered include: limiting reagents, Le Chatelier's principle, chemical kinetics, phase change, solubility and precipitation, and acid-base titration.

Related publications:


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