Calorimetry
Calorimetry is the experimental process of studying the conservation of heat energy in closed systems. According to the laws of thermodynamics, when matter is transformed through chemical or physical reactions, energy is released as heat or work. Calorimetry provides a measurement of the released heat.
For example, imagine the steam from a kettle operating a small paddlewheel. Some of the heat is retained by the water in the kettle and the escaping steam, some is absorbed by the surrounding air from the steam, and some is translated into the work necessary to move the paddlewheel. If you could measure the heat in the water and the heat absorbed by the air, you would find the sum of all the heat equaled the energy invested (supposedly by the stove) plus the energy transformed into work. Still, how could you measure the energy from all those sources? In the natural world, energy not retained by the transformed matter is absorbed by the environment too readily to be measured precisely. Through calorimetry, the environment of an experiment is isolated and controlled enough to be able to identify all sources of input (specifically, energy) and to measure precisely all necessary output, such as change in heat, transfer of energy, effects of heat, etc. The controlled environment through which the transfer of heat is measured is called the calorimeter.
Most calorimetric studies involve a calorimeter that consists of a container that, when closed, is completely insulated from outside heat. This container has enough room inside for a beaker or other vessel to hold the experimental material.
The calorimeter also includes a thermometer that can be read from the outside. The calorimeter serves as the controlled environment for the experiment. The goal of the controlled environment is to assure that conditions essential to the study of heat and heat transfer are measured and regulated. The temperature of the environment and equipment is recorded at the outset of the experiment, and the pressure of the environment is kept at a controlled level. The experimenter must also monitor the input and output energy. The only input energy should be that producing the heat as an independent variable. The output energy could be measured as heat or mechanical work. Whereas most calorimeters are designed to maintain a constant environmental temperature, the Bunsen ice calorimeter uses an encasement of ice for a low starting temperature. The substances placed into the calorimeter then heat up the ice. The volume of the melted ice is included as a measure of the heat transfer.
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