For calculation of entropy change of a system (interaction between extracellular polymeric substances and heavy metals), it is essential to assume equilibrium mixing values. How to achieve this "equilibrium" mixing in the isohermal titration calorimetry for the accurate calculation of entropy change of the reaction. Please suggest.
Monika Priyadarshanee
In your experiment, you need to place an aqueous solution of a polymer of a certain concentration in a calorimeter cell at a constant temperature (isothermal conditions). After this, it is necessary to drop another solution of a heavy metal salt into this solution. After the reaction begins, the temperature in the calorimeter cell will either increase or decrease. By changing the temperature you will determine the change in enalpy in the reaction. If you separately determine the equilibrium constant of the reaction, then use the formula to determine the change in the Gibbs energy of the reaction. Then, using these values, determine the change in entropy in the reaction.
With equilibrium mixing, the concentrations of substances in the cell must be constant. Polymer, salt, water should not be removed from the cell during the mixing process.
Yuri Mirgorod Thank you so much Sir for your valuable suggestion. It will be helpful.
Equilibrium mixing of entropy in Isothermal Titration Calorimetry (ITC) refers to the change in entropy that occurs when two solutions are mixed together at constant temperature to reach equilibrium. In ITC, a small amount of one solution (the titrant) is added to a larger amount of another solution (the sample) and the heat released or absorbed during the mixing process is measured. This heat is related to the change in enthalpy (ΔH) of the reaction.
However, when two solutions are mixed together, there is also a change in entropy (ΔS) due to the mixing process itself. This change in entropy can affect the overall thermodynamics of the reaction being studied. In ITC, the equilibrium mixing of entropy is accounted for by measuring the heat of dilution, which is the heat released or absorbed when the titrant is added to a reference solution that is identical to the sample solution except for the absence of the reactant being titrated. The heat of dilution represents the heat released or absorbed due to the mixing process alone and can be subtracted from the total heat measured during the titration to obtain the true enthalpy change of the reaction. This correction ensures that the measured enthalpy change is not affected by the entropy change due to mixing.
Yohannes Shuka Jara Thank you very much for the detailed explanation regarding ITC analysis. It will be helpful.
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