DTU Risø Campus Technical University of Denmark


Mass balance and Stoichiometry

In Chemsimul it is allowed to use symbols like "product" or "DUMMY" as well as standard chemical notation.
The program recognizes each individual molecule as a symbol and does not analyze it for atoms.

The mass balance is maintained for the whole reaction system and not for each reaction.


Stoichiometric balance

The GUI provides a stoichiometric check of each reaction as well as a check of consistency of possible symbols, when a standard chemical notation is used in the reaction system.

Atoms must be represented by either a single uppercase letter (e.g. H) or an uppercase letter followed by a lowercase letter (e.g. Na).

Symbols are written as a sequence of letters and digits (optional), starting with a lowercase letter (e.g. aSymbol3).

In any reaction, the same symbol must occur on one side only.

The consistency check means that first time a symbol occurs in the reaction system, its content of atoms is calculated.
The symbol must have the same content of atoms if it later occurs in the reaction system.

To access the stoichiometry test select the "miscellaneous" tab, and click "Check stoichiometric balance".

If you attempt a simulation, and Chemsimul detects a mass balance error, you will be warned, and if you click "Analyze" then the stoichiometry is checked.


  • Peter Kirkegaard
    Applied Mathematician, Ph.D.
    DTU - Risø Campus, Roskilde, Denmark
  • Erling Bjergbakke
    Bjergbakke Chemical Consulting
    Roskilde, Denmark
  • Jens V. Olsen
    System Programming Analyst
    DTU - Risø Campus, Roskilde, Denmark
  • Webmaster 17 Feb 2016