Reacting systems, Calorimetry

McCullough J P and Scott D W (eds) 1968 Experimental Thermodynamics Calorimetry of Non-Reacting Systems vol I (London Butterworths)... 

J. P. McCullough and D. W. Scott (eds.) Calorimetry of Non-Reacting Systems. New York Plenum Press, 1968. 

This section is concerned with calorimetry to determine the classification of the reacting system (as described in Chapter 4) so that appropriate relief sizing methods can be used. The measurement of data for relief sizing is described in A2.4 to A2.6 below, depending on the results of the classification of system type for relief sizing. 

J. W. Stout, Low-temperature calorimetry with isothermal shield and evaluated heat leak, in Experimental Thermodynamics, Vol. I Calorimetry of Non-Reacting Systems, J. P. McCullough and D. W. Scott, eds., Plenum Press, New York, 1968, Chapter 6, pp. 215-261. 

Changes in enthalpy of chemical reactions are determined by calorimetry of reacting systems. The reaction heat is calculated from measured heats of formation, solution, and mixing, using the Hess law. 

Calorimetry of non-reacting systems involves the measurement of heat capacity dependencies on temperature, which enables us to calculate the enthalpies of phase transformations. Based on the prevailing mode of the heat exchange between their individual parts, calorimeters for this purpose can be classified as low-, medium-, and high-temperature calorimeters. In the measurement of thermodynamic parameters of molten electrolytes, mostly the last two types of calorimeters are used. 

McCullough and Scott have edited a volume on behalf of the lUPAC Commission on Thermodynamics and Thermochemistry, devoted to the study of the calorimetry of non-reacting systems. The 24 contributors have supplied chapters covering the temperature range from below 20 K to very high temperatures. Temperature scales are discussed, but it is unfortunate that, although the book appeared in 1968, the article on temperature scales and temperature measurement was prepared too early to include reference to the IPTS-68. 

Some textbooks on calorimetiy are W. P. White, "The Modern Calorimeter." Chem. Catalog Co., New York, NY, 1928. W. Swietoslawski, "Microcalorimetry." Reinhold Publ., New York, NY, 1946. J. P. McCullough, "Experimental Thermodynamics, Vol. 1, Calorimetry of Non-reacting Systems." Plenum Press, New York, NY, 1968. W. Hemminger and G. Hohne, "Calorimetry." Verlag Chemie, Weinheim, 1984. J. M. Sturtevant, "Calorimetry," in A. Weissberger, B. W. Rossiter, eds., "Techniques of Chemistry," Vol. I, Part V. Wiley-Interscience, New York, NY, 1971. 

There are many ways to measure the concentrations of reacting species or species formed during the reaction, such as there are gc, UV-visible spectroscopy, IR spectroscopy, refiactometry, polarometry, etc. Conversion can be monitored by pressure measurements, gas-flow measurements, calorimetry, etc. Data are collected on a computer and many programmes are available for data analysis [3,4], The two-reaction system described above can be treated graphically, if it fulfils either the Bodenstein or Michaelis-Menten criteria. 

Adsorption calorimetry consists of the coupling of a heat flow calorimeter with a system able to monitor the adsorption of a probe molecule by determining the amount of probe gas that has reacted with the solid under study. It is probably the most direct method for describing in detail both the quantitative and energetic features of surface sites. The adsorption of a probe molecule is an exothermic phenomenon (AHj s < 0), while desorption processes are associated with endothermic peaks (AHdes > 0). Heats of reduction are generally associated with an... 

---