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# Tom

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1. ## Gas Units in React

So in order to have the mass transfer to the gas phase accounted for, it must be defined as a reactant? (and therefore can not be solved for?)
2. ## Gas Units in React

Tom, Thanks for your patience and quick replies. It appears from your replies and from calculations I have performed on values in the output files that the gas fugacity is actually a HYPOTHETICAL fugacity--it is the fugacity that would be in equilibrium with the solved solution composition (where the solved solution composition does not include mass transfer to the gas phase). Consistent with this interpretation, it appears that the the mass balance neglects the gas phase. Furthermore, suppressing CO2(g) results in an identical final solution composition. Again, although this is appropriate for the case of an effectively infinite gas buffer (e.g., ingassing from the atmosphere), it appears that REACT (at least in the case of how I have my model constructed) does not correctly simulate degassing. Specifically, the CO2(aq) values output by the model do not reflect any loss of CO2 to the gas phase (moles of CO2(aq) are consistently identical to moles of CaCO3 reacted, in spite of the rising CO2(g) fugacity). Is there a way to correctly simulate the degassing of CO2 during reaction using GWB? Example React_Output.txt Step # 0 Xi = 0.0000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.000 Ionic strength = 0.005363 Charge imbalance = 0.010726 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000000 kg Solution mass = 1.000011 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 11 mg/kg sol'n Elect. conductivity = 3220.17 uS/cm (or umho/cm) Hardness = 0.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 0.00 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-OH moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0009991 0.0000 0.0000 0.0000 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.01073 10.81 0.9323 -2.0000 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 2.798e-008 -7.553 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 9.87e-010 9.87e-010 3.96e-005 H+ 0.0107 0.0107 10.8 H2O 55.5 55.5 1.00e+006 HCO3- 9.87e-010 9.87e-010 6.02e-005 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 9.874e-010 9.874e-010 3.957e-005 Carbon 9.874e-010 9.874e-010 1.186e-005 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 10 Xi = 0.1000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.008 Ionic strength = 0.005463 Charge imbalance = 0.010726 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000002 kg Solution mass = 1.000021 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 19 mg/kg sol'n Elect. conductivity = 3166.29 uS/cm (or umho/cm) Hardness = 10.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 10.00 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0008992 9.991e-005 0.01000 0.003690 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.01053 10.61 0.9318 -2.0084 Ca++ 9.991e-005 4.004 0.7393 -4.1316 CO2(aq) 9.991e-005 4.397 1.0000 -4.0004 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.002831 -2.548 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 9.99e-005 9.99e-005 4.00 H+ 0.0106 0.0106 10.7 H2O 55.5 55.5 1.00e+006 HCO3- 9.99e-005 9.99e-005 6.10 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 9.991e-005 9.991e-005 4.004 Carbon 9.991e-005 9.991e-005 1.200 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 20 Xi = 0.2000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.017 Ionic strength = 0.005563 Charge imbalance = 0.010726 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000004 kg Solution mass = 1.000031 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 27 mg/kg sol'n Elect. conductivity = 3112.59 uS/cm (or umho/cm) Hardness = 20.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 20.00 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0007993 0.0001998 0.02000 0.007380 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.01033 10.41 0.9313 -2.0169 Ca++ 0.0001998 8.009 0.7375 -3.8316 CO2(aq) 0.0001998 8.793 1.0000 -3.6994 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.005663 -2.247 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000200 0.000200 8.01 H+ 0.0105 0.0105 10.6 H2O 55.5 55.5 1.00e+006 HCO3- 0.000200 0.000200 12.2 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0001998 0.0001998 8.009 Carbon 0.0001998 0.0001998 2.400 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 30 Xi = 0.3000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.026 Ionic strength = 0.005663 Charge imbalance = 0.010726 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000005 kg Solution mass = 1.000041 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 35 mg/kg sol'n Elect. conductivity = 3059.07 uS/cm (or umho/cm) Hardness = 30.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 30.00 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0006994 0.0002997 0.03000 0.01107 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.01013 10.21 0.9309 -2.0257 Ca++ 0.0002997 12.01 0.7358 -3.6565 CO2(aq) 0.0002997 13.19 1.0000 -3.5233 HCO3- 1.481e-008 0.0009038 0.9242 -7.8636 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.008494 -2.071 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000300 0.000300 12.0 H+ 0.0104 0.0104 10.5 H2O 55.5 55.5 1.00e+006 HCO3- 0.000300 0.000300 18.3 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0002997 0.0002997 12.01 Carbon 0.0002997 0.0002997 3.600 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 40 Xi = 0.4000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.035 Ionic strength = 0.005763 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000007 kg Solution mass = 1.000051 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 44 mg/kg sol'n Elect. conductivity = 3005.71 uS/cm (or umho/cm) Hardness = 40.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 40.00 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0005995 0.0003996 0.04000 0.01476 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.009927 10.00 0.9304 -2.0345 Ca++ 0.0003996 16.02 0.7341 -3.5326 CO2(aq) 0.0003996 17.59 1.0000 -3.3984 HCO3- 2.017e-008 0.001231 0.9236 -7.7298 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.01133 -1.946 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000400 0.000400 16.0 H+ 0.0103 0.0103 10.4 H2O 55.5 55.5 1.00e+006 HCO3- 0.000400 0.000400 24.4 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0003996 0.0003996 16.02 Carbon 0.0003996 0.0003996 4.800 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 50 Xi = 0.5000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.044 Ionic strength = 0.005863 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000009 kg Solution mass = 1.000061 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 52 mg/kg sol'n Elect. conductivity = 2952.52 uS/cm (or umho/cm) Hardness = 50.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 50.00 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0004996 0.0004996 0.05000 0.01845 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.009727 9.803 0.9299 -2.0436 Ca++ 0.0004996 20.02 0.7324 -3.4367 CO2(aq) 0.0004995 21.98 1.0000 -3.3014 HCO3- 2.576e-008 0.001572 0.9230 -7.6239 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.01416 -1.849 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000500 0.000500 20.0 H+ 0.0102 0.0102 10.3 H2O 55.5 55.5 1.00e+006 HCO3- 0.000500 0.000500 30.5 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0004996 0.0004996 20.02 Carbon 0.0004996 0.0004996 6.000 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 60 Xi = 0.6000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.053 Ionic strength = 0.005962 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000011 kg Solution mass = 1.000071 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 60 mg/kg sol'n Elect. conductivity = 2899.50 uS/cm (or umho/cm) Hardness = 60.00 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 59.99 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0003996 0.0005995 0.06000 0.02214 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.009527 9.602 0.9295 -2.0528 Ca++ 0.0005995 24.02 0.7307 -3.3585 CO2(aq) 0.0005994 26.38 1.0000 -3.2223 HCO3- 3.159e-008 0.001928 0.9225 -7.5354 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.01699 -1.770 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000599 0.000599 24.0 H+ 0.0101 0.0101 10.2 H2O 55.5 55.5 1.00e+006 HCO3- 0.000599 0.000599 36.6 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0005995 0.0005995 24.02 Carbon 0.0005995 0.0005995 7.200 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 70 Xi = 0.7000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.062 Ionic strength = 0.006062 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000013 kg Solution mass = 1.000081 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 68 mg/kg sol'n Elect. conductivity = 2846.64 uS/cm (or umho/cm) Hardness = 69.99 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 69.99 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0002997 0.0006994 0.07000 0.02583 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.009327 9.400 0.9290 -2.0622 Ca++ 0.0006994 28.03 0.7290 -3.2925 CO2(aq) 0.0006993 30.78 1.0000 -3.1553 HCO3- 3.769e-008 0.002300 0.9219 -7.4591 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.01982 -1.703 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000699 0.000699 28.0 H+ 0.0100 0.0100 10.1 H2O 55.5 55.5 1.00e+006 HCO3- 0.000699 0.000699 42.7 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0006994 0.0006994 28.03 Carbon 0.0006994 0.0006994 8.400 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 80 Xi = 0.8000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.072 Ionic strength = 0.006162 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000014 kg Solution mass = 1.000091 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 76 mg/kg sol'n Elect. conductivity = 2793.93 uS/cm (or umho/cm) Hardness = 79.99 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 79.99 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 0.0001998 0.0007993 0.08000 0.02952 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.009127 9.199 0.9286 -2.0719 Ca++ 0.0007993 32.03 0.7274 -3.2355 CO2(aq) 0.0007992 35.17 1.0000 -3.0973 HCO3- 4.406e-008 0.002688 0.9214 -7.3915 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.02265 -1.645 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000799 0.000799 32.0 H+ 0.00993 0.00993 10.0 H2O 55.5 55.5 1.00e+006 HCO3- 0.000799 0.000799 48.8 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0007993 0.0007993 32.03 Carbon 0.0007993 0.0007993 9.599 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 90 Xi = 0.9000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.082 Ionic strength = 0.006262 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000016 kg Solution mass = 1.000101 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 85 mg/kg sol'n Elect. conductivity = 2741.38 uS/cm (or umho/cm) Hardness = 89.99 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 89.99 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 9.991e-005 0.0008992 0.09000 0.03321 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.008927 8.997 0.9281 -2.0817 Ca++ 0.0008992 36.04 0.7258 -3.1853 CO2(aq) 0.0008991 39.57 1.0000 -3.0462 HCO3- 5.074e-008 0.003096 0.9208 -7.3305 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.02548 -1.594 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000899 0.000899 36.0 H+ 0.00983 0.00983 9.90 H2O 55.5 55.5 1.00e+006 HCO3- 0.000899 0.000899 54.9 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0008992 0.0008992 36.04 Carbon 0.0008992 0.0008992 10.80 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005 Step # 100 Xi = 1.0000 Temperature = 25.0 C Pressure = 1.013 bars pH = 2.092 Ionic strength = 0.006362 Charge imbalance = 0.010725 eq/kg (200% error) Activity of water = 1.000000 Solvent mass = 1.000018 kg Solution mass = 1.000111 kg Solution density = 1.013 g/cm3 Chlorinity = 0.000000 molal Dissolved solids = 93 mg/kg sol'n Elect. conductivity = 2688.98 uS/cm (or umho/cm) Hardness = 99.99 mg/kg sol'n as CaCO3 carbonate = 0.00 mg/kg sol'n as CaCO3 non-carbonate = 99.99 mg/kg sol'n as CaCO3 Rock mass = 0.000000 kg Carbonate alkalinity= 0.00 mg/kg sol'n as CaCO3 Water type = H-HCO3 moles moles grams cm3 Reactants remaining reacted reacted reacted ---------------------------------------------------------------------------- Calcite 7.149e-019 0.0009991 0.1000 0.03690 No minerals in system. Aqueous species molality mg/kg sol'n act. coef. log act. --------------------------------------------------------------------------- H+ 0.008728 8.796 0.9277 -2.0917 Ca++ 0.0009991 40.04 0.7242 -3.1405 CO2(aq) 0.0009990 43.96 1.0000 -3.0004 HCO3- 5.772e-008 0.003522 0.9203 -7.2747 (only species > 1e-8 molal listed) Mineral saturation states log Q/K log Q/K ---------------------------------------------------------------- (only minerals with log Q/K > -3 listed) Gases fugacity log fug. ----------------------------------------------- Steam 0.03131 -1.504 CO2(g) 0.02831 -1.548 In fluid Sorbed Kd Original basis total moles moles mg/kg moles mg/kg L/kg ------------------------------------------------------------------------------- Ca++ 0.000999 0.000999 40.0 H+ 0.00973 0.00973 9.80 H2O 55.5 55.5 1.00e+006 HCO3- 0.000999 0.000999 61.0 Elemental composition In fluid Sorbed total moles moles mg/kg moles mg/kg ------------------------------------------------------------------------------- Calcium 0.0009991 0.0009991 40.04 Carbon 0.0009991 0.0009991 12.00 Hydrogen 111.0 111.0 1.119e+005 Oxygen 55.51 55.51 8.881e+005
3. ## Gas Units in React

That doesn't make sense (unless I am missing something here). Sure, it works fine if you are trying to define a boundary condition. However, in the case where a gas is generated during reaction (e.g., CO2 exsolved during carbonate dissolution) GWB is clearly converting a finite mass of the species CO2(g) into a pressure (atm). To do so, a unit volume must be assumed (remember: PV=nRT). For the same amount of dissolution (and identical speciation) the fugacity (or partial pressure) would be completely different depending on the assumed size of the gas reservoir in contact with the mineral/solution mixture. When defining a boundary condition (e.g., atmospheric CO2) this reservoir is of infinite volume and a pressure is sufficient (n is assumed not to change, even though it is lost to the solution). However, when generating a finite mass of a gas it seems that the program must be assuming a unit volume of some sort, much like a unit volume of 1 liter (55 moles) is assumed for the solvent. What am I missing? How do I take the CO2(g) fugacity reported and calculate the mass of CO2(g) released from solution?

5. ## Gas Units in React

I understand that gas is set in units of Fugacity in React. However, for output (e.g., when plotting CO2(g) exsolved as a function of rxn progress for carbonate dissolution), this unit has little meaning without the associated volume. What is the unit volume (for gas) assumed by React? I would like to use the volume to calculate a mass exsolved from the reported fugacity.
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