Accurate heat capacity determination of solids and liquids using a heat conduction calorimeter

Abstract

This study investigates the suitability of heat conduction calorimeters for determining the specific heat capacity of solid and liquid substances. Accurate and precise measurements were obtained for various substances, including water, ethylene glycol, the ionic liquid [EMIM][TCM], and copper, with relative standard deviations averaging less than 1%. Measurements on [EMIM][DCA] indicated a systematic deviation from the literature values. The study highlights the repeatability of the measurement method, which worked well for both temperature increases and decreases, as well as for the mean of the two. The influence of sample size on the results when it came to liquids was also investigated, revealing that large sample sizes led to underpredictions; while, small sizes yielded the opposite effect. The best results were obtained with half-filled vials; a similar filling level as was used in the electrical calibrations of the calorimeters with heaters in the vials. Additionally, no significant differences were observed among the eight calorimeters of the I-Cal Flex instrument, and different baseline calculation methods had negligible impact on the results. Overall, this study illustrates how a heat conduction calorimeter can be utilized for accurate and precise heat capacity measurements for both solid and liquid substances.