File:Energy; work, heat and transformations (1909) (14765962442).jpg

Identifier: energyworkheattr00reev (find matches)
Title: Energy; work, heat and transformations
Year: 1909 (1900s)
Authors: Reeve, Sidney A. (Sidney Armor), 1866-1941
Subjects: Thermodynamics
Publisher: New York, McGraw-Hill Book Company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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dH c Q a FIG. 8a. THE THERMAL DIAGRAM 101 The latent heat of vaporization is shownby the area beneath DE, or dDEe. It is muchgreater than the latent heat of fusion, asshown by comparing this area with CAOc.In this case there is no doubt as to theincrease in volume. The volume of eachmolecule after popping is several hundredtimes that before, the ratio depending uponthe pressure under which vaporization occurs. Indeed, this increase in volume is so greatthat it expands into visibility an energy-quantity which has hitherto been negligible.This is the external work. The energysupplied to each molecule along DE con-sists not only of that required to burst
Text Appearing After Image:
THE MINIMUM LIMIT OF TEMPERATURE FIG. 8b. 102 ENERGY the molecule against its own internal bonds of unity, called thedisgregation-workj^ but the external forces must be pushed backalso, throughout a considerable increase in volume. Yet in thiscase the external work amounts only to about one-ninth to one-fifteenth of the disgregation-work, so powerful are the congre-gative molecular forces. If the pressure upon the heated water had been higher thanthat permitting vaporization at D, that process would have beendelayed until some higher temperature had been reached, as atD. Therefore, there may be as many different vaporization-levels as there are different pressures. The ends of these variousmetamorphic lines, such as DE, DE, etc., form a curve SS whichis called the saturation-curve. But the student is especiallywarned against thinking of the saturation-curve as representinga process, as do most of the other curves in the thermal diagram.There is no process known to the boiler or engine

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