modelCarbonDioxideInWater

CO2 as alone acid-base buffer

Extends from Modelica.Icons.Example (Icon for runnable examples).

Information

CO2 solution in water without any other acid-base buffers.

plotExpression(apply(-log10(CarbonDioxideInWater.H3O.solute)), false, "pH", 1);


Please note, that OH- (and CO3^-2) can be neglected from electroneutrality calculation, because of very small concentrations (in physiological pH) anyway.

And if SID>0 then also H3O+ can be also neglected from electroneutrality, because only bicarbonate anions HCO3- (or CO3^-2) are needed there to balance the electroneutrality.


The partial pressure of CO2 in gas are input parameter. Outputs are an amount of free dissolved CO2 in liquid and an amount of HCO3-.


The titration slope der(pH)/der(SID)=17.5 1/(mol/L) at pH=7.4 and pCO2=40 mmHg.


Molar heat of formation (aqueous):

CO2: -413.5 kJ/mol (gas: -393.5 kJ/mol )

H2O: -285.8 kJ/mol

HCO3-: -692.0 kJ/mol

CO3^-2: -677.1 kJ/mol


Enthalphy of reaction H2O + CO2 <-> HCO3- + H+ : 7.3 kJ/mol

Enthalphy of reaction HCO3- <-> CO3^-2 + H+ : 14.9 kJ/mol

Components

TypeNameDefaultDescription
Components.SubstanceHCO3
Components.ChemicalReactionHendersonHasselbalch
Sources.UnlimitedGasStorageCO2_gas
Components.SubstanceH3O
Components.GasSolubilitygasSolubility
Components.SubstanceCO2_liquid
SteadyStates.Components.ElementaryChargeConservationLawelectroneutralitystrong ion difference of solution
Components.SubstanceCO3
Components.ChemicalReactionc2
Modelica.Blocks.Math.GaintoColoumnfrom elementary charge to to electric charge, which is needed in system
Modelica.Blocks.Sources.ContinuousClockSIDstrong ions difference with respect to albumin charge shift

Revisions

2014

Marek Matejak, Charles University, Prague, Czech Republic