| Popis: |
Calorimetry has been used to measure rates of reaction since the late 1700s when Antoine Lavoisier used an ice calorimeter to measure the rate of heat produced by a guinea pig (Lavoisier and LaPlace 1780). In proving that respiration was simply a slow combustion, Lavoisier also measured the rates of consumption of oxygen and production of CO2. Lavoisier’s experiments demonstrate many of the advantages of calorimetry for kinetic measurements; rates can be measured directly and noninvasively in any media. Measurements of rates instead of measuring the amount of product accumulated over time (or of reactant lost) are faster, simpler, and more sensitive than most other methods, particularly for slow reactions. Aside from methods that count radioactive decay rates, heat conduction and power compensation calorimetry are the only methods that measure rates directly. Calorimetry has been shown to be capable of measuring rates of reactions with half-lives greater than 1000 years (Hansen 1996). Calorimetry makes no requirements of the system except that it fits within the reaction vessel and not react with any other materials in the reaction vessel. Systems can be gaseous, liquid, solid, or even a living organism, e.g., plant tissue, insects, microorganism cultures, and animals. |
