The Reaction Thermodynamics subnode (), the Enthalpy of Reaction (J/mol) of each reaction can be specified. This node overrides all the automatically calculated reaction enthalpies as defined in the Species Thermodynamics subnode.

Add the Reaction Thermodynamics node from the Chemistry toolbar, Attributes menu. Alternatively, when the Feature Nodes Available for the Chemistry Interface check box is selected on the Chemistry interface Settings window, right-click a Reversible Reaction Group or Equilibrium Reaction Group to add the Reaction Thermodynamics subnode.