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- Persson, Anna, et al.
(författare)
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Scaling up effects in the organic laboratory
- 2004
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Ingår i: Journal of Chemical Education. - 0021-9584. ; 81:9, s. 1353-1354
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Tidskriftsartikel (refereegranskat)abstract
- A simple, yet safe and effective set of experiments to expose chemistry students to some of the effects that may be encountered when scaling up an organic reaction is described. The exothermic Diels–Alder reaction between maleic anhydride and cyclopentadiene was found to be ideal for our purposes and was performed in small, medium, and large scale for comparison. The observed differences of heat evolution between the three scales were significant. Also, to demonstrate how excess heat evolution can be controlled by simple means, two additional experiments in which the reaction was run either with small glass helices or water present were performed. The experiments were combined with some simple calculations that provided graphic illustrations of the observed differences, which aided the students in their understanding of the topic. This assignment can easily be adapted to work with both small and large groups of students.
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- Wadsö, Lars, et al.
(författare)
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The isothermal heat conduction calorimeter: a versatile instrument for studying processes in physics, chemistry and biology
- 2001
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Ingår i: Journal of Chemical Education. - 0021-9584. ; 78:8, s. 1080-1086
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Tidskriftsartikel (refereegranskat)abstract
- An approach to teaching calorimetry is offered through practical, versatile undergraduate experiments using an isothermal heat conduction calorimeter, which measures a variety of heat changes--enthalpies of phase changes, hydration, dissolution, adsorption and desorption, and reaction--as well as the metabolic rate of living organisms. Isothermal heat-conduction calorimetry is contrasted with adiabatic calorimetry. The general design and calibration of an instrument is discussed and five student experiments are described: heat capacity of solids, enthalpy of acid-base reaction, enthalpy of vaporization, hydration of cement, and metabolic rates of insects.
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