Determination of the Temperature Change by Means of an Outcoming Signal of Electric Resistance in an Isoperibolic Calorimetric Cell. Obtainment of Heat Solution

An isoperibolic calorimetric cell is built with glass surrounded by plastic insulation. Thecell has a lid on which a thermistor thermometer, an electric resistance to provide the cell with definitequantities of electric work and a container for a glass ampoule, are placed. For measuring the thermalchanges, an NTC thermistor, which provides an electric resistance signal that varies with temperature,is used. Calibration curves of the thermistor and of the stabilization of the system signal in thermalequilibrium are shown, which enable the observation of a good insulation. The calorific capacity of thesystem with water, with a value of 206.7 ± 0.7 J °C-1 is determined; the solution enthalpy for propanolwaterand KCl-water systems is obtained, which shows the behavior of the cell before exothermic andendothermic effects, respectively.