Determination of Thermodynamic Parameters Using Digital Image-Based Method

Seeking to foster the learning process and encourage the active participation of undergraduate students, this work proposes a new methodology that involves integrating smartphones into the learning process under a simple and accessible approach to learning in Chemistry and Physics laboratories aiming at facilitating the learning of some chemical concepts, such as thermodynamics and chemical equilibrium. Using RGB model data collected from images captured by students' smartphones, the Delta H degrees, Delta S degrees, and Delta G degrees values of a colorimetric reaction with cobalt complexes were obtained using the equilibrium constant (K-eq) and the concentrations of two complex cobalt ions at varying temperatures. The values obtained from the experiments conducted by the students were in agreement with those reported in the literature at 95% confidence level. The main pedagogical objective of this experiment was to show that based on digital images obtained from a smartphone, one can understand basic physical-chemistry concepts, taught in undergraduate courses, through the application of a simple methodology based on a widely accessible, low-cost technological device, and obtain results similar to those of UV-vis spectrophotometry. The use of digital images led to better assimilation of the concepts of reflectance and absorbance. The students considered the experimental procedure to be positively surprising, since they could use their smartphones to carry out the experiment. This work also presents a step-by-step guide for the acquisition of thermodynamic data using digital images from a smartphone.