Elements of chemistry : including the recent discoveries and doctrines of the science / by Edward Turner.

  • Turner, Edward, 1798-1837.
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry : including the recent discoveries and doctrines of the science / by Edward Turner. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    The rate of expansion of atmospheric air at temperatures exceeding 212° has been examined by MM. Dulong and Petit, and the following Table contains the result of their observations. {Jin. de Ch. et Jt Ph. vU. 120.) Temperature by the Corresponding Mercurial Thermometer. volumes of a given volume Fahrenheit. Centigrade. of air. — 33° - 36° 0.8650 32 0 1.0000 212 100 1.3750 302 150 1.5576 392 200 1.7389 482 250 1.9189 572 300 2.0976 * pcury boils 680 360 2.3125 Hydrogen gas was found to expand in the same proportion; so that all gases may be inferred to expand to the same extent, for equal in- graduated tube at 48° F., how many will it fill at 60° F? Here P' = 100; T=48—32 or 16; T'=60—32, or 28. The number sought, or the „„ 100x508 496 -=102.42.* * To those who are not algebraists, the following explanation and cal- culation may be useful. As every gas expands l-480th of the volume it would occupy at 32°, for every degree of Fahrenheit's thermometer, it is clear that it will expand 1-481st part of its volume at 33°, l-482d part of its volume at 349, and so on for each successive addition of one degree of caloric. In order to know, therefore, the fractional dilatation of a gas at any temperature above 32°, for a single degree, it is only necessary to add to the denominator of the fraction 1-480, a number of units equal to the number of degrees that the gas exceeds the tempe- rature of 32°. Thus a gas at the temperature of 42° will expand l-490th, at 52? 1-500, of its volume, for every increment of heat equal to one degree. Knowing in this simple manner the fractional amount of ex- pansion of a gas at any temperature for one degree, we multiply this amount by the difference between the existing temperature and the temperature to which it is desired to reduce the volume. If the reduc- tion is to a higher temperature, this product is added to the existing volume; if to a lower, subtracted. Thus, to calculate the example which Dr. Turner has selected, namely, 100 measures of a gas at 48°, what will be its bulk at 60°, we proceed as follows: as the existing temperature is 16° above 32°, its fractional expansion for one degree will be 1-480+16=1-496. Taking the 496th part of one hundred, the given volume, we have the actual expansion for one degree. This, up- on calculation, will be found to be .2016, which multiplied by 12, the difference between the actual temperature and the temperature of the volume sought, will give 2-419, as the actual expansion, corresponding to 12 degrees. As the temperature of the volume sought is above the original temperature, this number must be added to the given volume. So that 100+2-419 = 102-419 will be the volume sought. B.