 Calorimetry may be used to monitor the course of a reaction, since the instantaneous heat flux of the reaction, which is directly related to the enthalpy change for the reaction, is monitored.Reaction calorimetry may be classified as a differential technique since the primary data collected are proportional to rate vs. time.From these data, the starting material or product concentration over time may be obtained by simply taking the integral of a polynomial fit to the experimental curve.