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PHASESFix_H+H+ = H+log_k 0.0ENDSOLUTION 1 -temperature 25 -pH 7 charge-units mol/kgwNa 0.1Cl 0.1EQUILIBRIUM_PHASES 1Calcite 0 10fix_H+ -5 HClEND

K(Calcite) = act(Ca+2)*act(CO3-2) or logK = Log10(act(Ca+2)) + Log10(act(CO3-2))

log K = -8.48 log10(act(Ca+2)) + log10(act(CO3-2)) = -1.222 + -7.258 = -8.480

SOLUTION 1ENDSOLUTION 2-density 1 calc-units mol/LpH 1 chargeCl 10ENDUSER_GRAPH10 GRAPH_X TOT("Cl")20 GRAPH_Y -LA("H+")ENDEQUILIBRIUM_PHASES 1Calcite 0 100ENDMIX1 12 0.03USE equilibrium_phases 1ENDMIX1 12 0.04USE equilibrium_phases 1ENDMIX1 12 0.05USE equilibrium_phases 1END