User`s manual

16 Chapter 3: Theory of Operation
Calorimetry Sciences Corp.
CSC 5300 N-ITC III 17
User’s Manual
Titration/Data Analysis
A single titration calorimetric experiment yields heat data as a function of the ratio of the
concentrations of the reactants. Titration data, in the form of heat change versus volume
of titrant added, can be examined for both analytical (thermometric titrimetry) and
thermodynamic (titration calorimetry) information.
Other corrections must be made to the heat data to account for heat effects associated
with titrant dilution and any temperature difference between titrant and titrate solutions.
These corrections are most easily accomplished by performing a blank titration
experiment and subtracting the blank heat data from the experimental thermogram.
In the case of quantitative reaction of added titrant, the analysis of the thermogram is
quite simple. All peak areas will be the same (with the possible exception of the last peak)
and ∆H calculated from the incremental heat and the number of moles of titrant added per
increment. The titrant concentration is calculated from the total heat divided by the ∆H
for the reaction.
Calculation of Equilibrium Constants
The equilibrium constant for a given reaction may be simultaneously determined with the
enthalpy change, if the magnitudes of K and ∆H for the overall reaction taking place in
the calorimeter are within certain limits. The family of curves presented in Figure 3-5a
Figure 3-5: Dependence of calorimetric data on (a) K
eq
and (b) ∆H
R
for the titration of A with B.