Structure of thermodynamic data sets

Element Master species Alkalinity mole mass in mg/L atomic mass of elements 

The contribution of each master species to the alkalinity in Table 22 is calculated according to the predominant species at a pH of 4.5. For example, Fe3+ forms at pH 4.5 the predominant species Fe(OH)2+ with two OH -ions that are able to bind two H+-ions. Therefore a factor of -2 results for the alkalinity. For inorganic C with the dominant species H2C03 and two FT -ions the factor will be +2. 

Column 4 in Table 22 specifies in which way the input in mg/L has to be done. In this example, C has to be defined as carbonate, however, nitrate, nitrite, ammonia each defined as elementary nitrogen, P as elementary phosphorous, S as sulfate and Si as Si02. If, for example, P is input as phosphate in mg/L, all 

For all reactions being put in data sets manually, the used master species, if not yet existent, have to be defined using the keyword SOLUTION MASTER SPECIES. 

For the species in solution (SOLUTIONSPECIES, Table 23), listed in the top row with current number, solubility constant log k and enthalpy delta h are given in kcal/mol or kJ/mol at a temperature of 25 °C. Using the sub-key-word gamma parameters for the calculation of the activity coefficient y according the WATEQ-DEBYE-HUCKEL ion dissociation theory (compare to chapter 1.1.2.6.1) are given. With the sub-key-word analytical , coefficients At to A5 are defined to calculate the temperature dependence of the solubility-product constant. 

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