This example:
In the [Reactants Window] there are 4 reactants (Inflows):
55.508 H2O + 0.3 HC2H3O2 + 0.3 NaC2H3O2 + <A> NaOH =
OLI options in effect: 'Include Redox' - this permits the dissociation reaction NaOH = Na[+](aq) + OH[-](aq).
The amount alpha, <A>, of NaOH is not specified in the [Reactants Window]. Depending up on the type of calculation being performed, <A> may be set in the [Menu Window] (as in this present example) or calculated in the equilibrium (in which case <A> would be called the target variable).
In the [Menu Window] in order to simplify the example only 5 aqueous species have been selected (click mouse-right-button on aqueous '+' to open the [Selection Window]): H[+], OH[-], Na[+], and the acid/base pair HC2H3O2/C2H3O2[-].
<A> is given the range '0 1 0.01' (i.e. 0, 0.01, 0.02 ..0.1 M NaOH), the product T and P are 25 C and 1 atm.
All data are taken from OLIP (Public.ddb) - the OLI Systems public databank. For this example to work both FactSage and the OLI StreamAnalyzer must be installed on the PC, and the OLIP (Public.ddb) databank must included in the list of databases.
The following show the Equilib results at 0 mol NaOH (<A> = 0) where pH = 4.624, and 0.02 M NaOH (<A> = 0.02) where pH = 4.679. For comparison purposes, the results are also presented for 0.02 M NaOH in the absence of the acid/base buffer where pH = 12.236.
Eh is not calculated because the aqueous phase is restricted and the gas phase is absent.
--------------------------------------------------------- FactSage results at 0 mol NaOH (<A> = 0) where pH = 4.624 OLI options in effect: 'Include Redox' --------------------------------------------------------- [FACT Format] 55.508 H2O + 0.3 HC2H3O2 + 0.3 NaC2H3O2 + <A> NaOH = 1.0000 mol ( 55.508 H2O + 0.29997 C2H4O2_ACETACIDAQ + 0.30003 C2H3O2[-1]_ACETATEION + 0.30000 Na[+1]_NAION + 0.33400E-04 H[+1]_HION + 0.56346E-09 HO[-1]_OHION) ( 25.00 C, 1 atm, aqu_OLI) (Eh= ---- V, pH= 4.624) where "A" on the reactant side is 0.0000 **************************************************************** H G V S Cp (J) (J) (l) (J/K) (J/K) **************************************************************** -1.62114E+07 -1.74233E+07 1.14517E+00 4.06480E+03 2.30531E+03 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [ChemSage Format] T = 25.00 C P = 1.00000E+00 atm V = 1.14517E+00 dm3 STREAM CONSTITUENTS AMOUNT/mol H2O/aqu_OLI/ 5.5508E+01 C2H4O2_ACETACIDVAP(g) 3.0000E-01 C2H3NaO2_NAACETAQ(aq) 3.0000E-01 NaOH(s0) 0.0000E+00 EQUIL AMOUNT MOLALITY ACTIVITY PHASE: aqu_OLI mol H2O 5.5508E+01 5.5508E+01 9.8396E-01 C2H4O2_ACETACIDAQ 2.9997E-01 2.9997E-01 3.0728E-01 HO[-1]_OHION 5.6346E-10 5.6347E-10 4.2015E-10 H[+1]_HION 3.3400E-05 3.3401E-05 2.3774E-05 Na[+1]_NAION 3.0000E-01 3.0000E-01 2.1192E-01 C2H3O2[-1]_ACETATEION 3.0003E-01 3.0004E-01 2.1194E-01 TOTAL: 5.6408E+01 1.0000E+00 ******************************************************************** Cp_EQUIL H_EQUIL S_EQUIL G_EQUIL V_EQUIL J.K-1 J J.K-1 J dm3 ******************************************************************** 2.30531E+03 -1.62114E+07 4.06480E+03 -1.74233E+07 1.14517E+00 Properties for aqu_OLI: pH = 4.6239 Total solute molality = 0.9000 Ionic strength = 0.3000 Osmotic coefficient = 0.9973 Debye-Hueckel slope = 0.3915 Density/mol.dm-3 = 54.6288 Absolute viscosity/cP = 1.0114 Diffusivities/m2.sec-1: H2O 2.3412E-09 C2H4O2_ACETACI 1.2266E-09 HO[-1]_OHION 5.0117E-09 H[+1]_HION 8.7910E-09 Na[+1]_NAION 1.3147E-09 C2H3O2[-1]_ACE 1.0890E-09 Mole fraction of system components: aqu_OLI Na 1.7511E-03 O 3.3100E-01 C 7.0043E-03 H 6.6025E-01 System density/g.cm-3 = 0.910445
------------------------------------------------------------- FactSage results at 0.02 M NaOH (<A> = 0.02) where pH = 4.679 OLI options in effect: 'Include Redox' ------------------------------------------------------------- [FACT Format] 55.508 H2O + 0.3 HC2H3O2 + 0.3 NaC2H3O2 + <A> NaOH = 1.0004 mol ( 55.508 H2O + 0.27987 C2H4O2_ACETACIDAQ + 0.31991 C2H3O2[-1]_ACETATEION + 0.31988 Na[+1]_NAION + 0.29597E-04 H[+1]_HION + 0.64037E-09 HO[-1]_OHION) ( 25.00 C, 1 atm, aqu_OLI) (Eh= ---- V, pH= 4.679) where "A" on the reactant side is 0.2000E-01 **************************************************************** H G V S Cp (J) (J) (l) (J/K) (J/K) **************************************************************** -1.62219E+07 -1.74341E+07 1.14556E+00 4.06571E+03 2.30680E+03 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [ChemSage Format] T = 25.00 C P = 1.00000E+00 atm V = 1.14556E+00 dm3 STREAM CONSTITUENTS AMOUNT/mol H2O/aqu_OLI/ 5.5508E+01 C2H4O2_ACETACIDVAP(g) 3.0000E-01 C2H3NaO2_NAACETAQ(aq) 3.0000E-01 NaOH(s0) 2.0000E-02 EQUIL AMOUNT MOLALITY ACTIVITY PHASE: aqu_OLI mol H2O 5.5528E+01 5.5508E+01 9.8367E-01 C2H4O2_ACETACIDAQ 2.7997E-01 2.7987E-01 2.8732E-01 HO[-1]_OHION 6.4060E-10 6.4038E-10 4.7637E-10 H[+1]_HION 2.9608E-05 2.9597E-05 2.0962E-05 Na[+1]_NAION 3.2000E-01 3.1989E-01 2.2474E-01 C2H3O2[-1]_ACETATEION 3.2003E-01 3.1992E-01 2.2476E-01 TOTAL: 5.6448E+01 1.0000E+00 ******************************************************************** Cp_EQUIL H_EQUIL S_EQUIL G_EQUIL V_EQUIL J.K-1 J J.K-1 J dm3 ******************************************************************** 2.30680E+03 -1.62219E+07 4.06571E+03 -1.74341E+07 1.14556E+00 Properties for aqu_OLI: pH = 4.6786 Total solute molality = 0.9197 Ionic strength = 0.3199 Osmotic coefficient = 0.9938 Debye-Hueckel slope = 0.3915 Density/mol.dm-3 = 54.6872 Absolute viscosity/cP = 1.0171 Diffusivities/m2.sec-1: H2O 2.3394E-09 C2H4O2_ACETACI 1.2257E-09 HO[-1]_OHION 4.9797E-09 H[+1]_HION 8.7228E-09 Na[+1]_NAION 1.3104E-09 C2H3O2[-1]_ACE 1.0857E-09 Mole fraction of system components: aqu_OLI Na 1.8672E-03 O 3.3100E-01 C 7.0018E-03 H 6.6013E-01 System density/g.cm-3 = 0.910839
---------------------------------------------------------------------- FactSage results at 0.02 M NaOH in the absence of the acid/base buffer - pH = 12.236 OLI options in effect: 'Include Redox' ---------------------------------------------------------------------- [FACT Format] 55.508 H2O + 0 HC2H3O2 + 0 NaC2H3O2 + NaOH = 1.0000 mol ( 55.508 H2O + 0.20000E-01 HO[-1]_OHION + 0.20000E-01 Na[+1]_NAION + 0.67156E-12 H[+1]_HION) ( 25.00 C, 1 atm, aqu_OLI) (Eh= ---- V, pH=12.236) where "A" on the reactant side is 0.2000E-01 **************************************************************** H G V S Cp (J) (J) (l) (J/K) (J/K) **************************************************************** -1.58582E+07 -1.70355E+07 1.12142E+00 3.94874E+03 2.26912E+03 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [ChemSage Format] T = 25.00 C P = 1.00000E+00 atm V = 1.12142E+00 dm3 STREAM CONSTITUENTS AMOUNT/mol H2O/aqu_OLI/ 5.5508E+01 C2H4O2_ACETACIDVAP(g) 0.0000E+00 C2H3NaO2_NAACETAQ(aq) 0.0000E+00 NaOH(s0) 2.0000E-02 EQUIL AMOUNT MOLALITY ACTIVITY PHASE: aqu_OLI mol H2O 5.5508E+01 5.5508E+01 9.9931E-01 HO[-1]_OHION 2.0000E-02 2.0000E-02 1.7477E-02 H[+1]_HION 6.7156E-13 6.7157E-13 5.8042E-13 Na[+1]_NAION 2.0000E-02 2.0000E-02 1.7477E-02 TOTAL: 5.5548E+01 1.0000E+00 ******************************************************************** Cp_EQUIL H_EQUIL S_EQUIL G_EQUIL V_EQUIL J.K-1 J J.K-1 J dm3 ******************************************************************** 2.26912E+03 -1.58582E+07 3.94874E+03 -1.70355E+07 1.12142E+00 Properties for aqu_OLI: pH = 12.2363 Total solute molality = 0.0400 Ionic strength = 0.0200 Osmotic coefficient = 0.9600 Debye-Hueckel slope = 0.3915 Density/mol.dm-3 = 55.3034 Absolute viscosity/cP = 0.9073 Diffusivities/m2.sec-1: H2O 2.2866E-09 C2H4O2_ACETACI 1.2009E-09 HO[-1]_OHION 5.1579E-09 H[+1]_HION 9.1285E-09 Na[+1]_NAION 1.3202E-09 C2H3O2[-1]_ACE 1.0910E-09 Mole fraction of system components: aqu_OLI Na 1.2006E-04 O 3.3333E-01 H 6.6655E-01 System density/g.cm-3 = 0.892437