Viewing thermo datasets in TEdit

From GWB apps, File → View → …\thermo.tdat From TEdit, File → Open → Thermo Data… → …\thermo.tdat From Windows explorer, double-click the file You can launch TEdit to view thermo datasets in several different ways. GWB’s default dataset.

# of elements, species, etc. in the dataset The “B-dot” equation is used to calculate activity coefficients. The Header section contains a description of the thermo dataset’s content and bibliographic information. Literature sources for thermo data

Pressure is by default 1 atm up to 100 °C, then follows the steam saturation curve. Parameters for calculating activity coefficients. The Tables section contains eight principal temperatures at which activity coefficient parameters and log K’s are compiled. Data compiled from 0 to 300 °C

Click to expand list. Click to view the entry. The Elements from which all species in the dataset are composed are defined here. Each entry includes a name, symbol, and molecular weight.

HCO 3 − is composed of 1 H, 1 C, and 3 O. The Basis species from which all reactions are constructed are defined here. Each entry includes a name, charge, ion size parameter, and molecular weight. Basis species are composed of elements defined in the previous section.

The Redox couples are Basis species in a different oxidation state. Negative coefficient for species on the left side of the reaction Species defined earlier in the dataset Log K for the reaction at the principal temperatures Their entries additionally include a reaction involving the Basis species.

Filter on Elements or Basis and redox species Click on any section to enable filtering of species in the dataset. Select C, then click Filter to show only species containing carbon…

All other species to be considered are known as Aqueous species. …only species containing carbon are listed. Log K for the reaction at the principal temperatures Their entries include a reaction for dissociating to the Basis or redox species. The reaction should be written without change in oxidation state, if possible.

The Free electron is included in datasets considering redox reactions. When O 2 (aq) is the redox pivot (like in thermo.tdat), the electron must be balanced in terms of O 2 (aq) or O 2 (g).

Optional information for minerals The Minerals are formed from either the Basis or Redox species. Like with the Aqueous species and later sections, the reaction should be written without change in oxidation state, if possible.

The Gases are formed from either the Basis or Redox species. CH 4 (g) is balanced in terms of the Redox species CH 4 (aq)

The Oxide components are fictive entries used to describe bulk composition. They have no thermodynamic stability and hence there are no entries for log K values.

For more details, see the “Thermo Datasets Appendix” in the GWB Reference Manual.