Unformatted text preview: quite different from raising a weight since the organized
paddle-wheel energy is now converted to a highly disorganized form of
energy, which cannot be converted back to the paddle wheel as the rotational
kinetic energy. Only a portion of this energy can be converted to work by
partially reorganizing it through the use of a heat engine. Therefore, energy is
degraded during this process, the ability to do work is reduced, molecular disorder is produced, and associated with all this is an increase in entropy.
The quantity of energy is always preserved during an actual process (the
first law), but the quality is bound to decrease (the second law). This decrease
in quality is always accompanied by an increase in entropy. As an example,
consider the transfer of 10 kJ of energy as heat from a hot medium to a cold
one. At the end of the process, we will still have the 10 kJ of energy, but at a
lower temperature and thus at a lower quality.
Heat is, in essence, a form of disorganized energy, and some disorganization
(entropy) will flow with heat (Fig. 7–24). As a re...
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This document was uploaded on 11/28/2012.
- Spring '09