Journal of Undergraduate Research
Keywords
pressure perturbation calorimetry, Apparent Molar Heat Capacities, aqueous solutions, N-DSC
College
Physical and Mathematical Sciences
Department
Chemistry and Biochemistry
Abstract
In Dr. Woolley’s lab we have made extensive measurements of the Apparent Molar Heat Capacities of aqueous solutions using a Nano Differential Scanning Calorimeter, N-DSC (Calorimetry Science Corporation, Spanish Fork, UT). Through modifications to the N-DSC we are now able to do pressure perturbation calorimetry. That is to say we may now change the pressure of a solution and measure the change in the heat of that solution, (dq/dP)T ( as opposed to (dq/dT)p which is heat capacity). This property is related to entropy by the 2nd law of thermodynamics in the following way (dq/dP)T = T(dS/dP)T. From a Maxwell relation we see that (dS/dP)T = -(dV/dT)p which is defined as expansibility. In combining the two relationships we obtain (dq/dP)T = -T(dV/dT)p, therefore by measuring how the heat changes as we change the pressure of a solution we may obtain expansibility.
Recommended Citation
Brown, Blair R. and Woolley, Dr. Earl M.
(2013)
"Pressure Perturbation Calorimetry,"
Journal of Undergraduate Research: Vol. 2013:
Iss.
1, Article 2527.
Available at:
https://scholarsarchive.byu.edu/jur/vol2013/iss1/2527