3 calories are evolved. In both
cases, however, the heat attainable is limited by the fact that at
certain temperatures hydrogen and oxygen refuse to combine to form water,
and carbon and oxygen refuse to form carbon dioxide--in other words,
water vapour and carbon dioxide dissociate and absorb heat in the process
at certain moderately elevated temperatures. But when 1 atom of solid
amorphous carbon unites with 1 atom of oxygen to form carbon monoxide,
29.1 [Footnote: Cf. Chapter VI., page 185.] large calories are produced,
and carbon monoxide is capable of existence at much higher temperatures
than either carbon dioxide or water vapour. In any gaseous hydrocarbon,
again, the carbon exists in the gaseous state, and when 1 atom of the
hypothetical gaseous carbon combines with 1 atom of oxygen to produce 1
molecule of carbon monoxide, 68.2 large calories are evolved. Thus while
solid amorphous carbon emits more heat than a chemically equivalent
quantity of hydrogen provided it is enabled to combine with its higher
proportion of oxygen, it emits less if only carbon monoxide is formed;
but a higher temperature can be attained in the latter case, because the
carbon monoxide is more permanent or stable.
Pages:
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572