The Romance of Modern Chemistry
Forfatter: James C. Phillip
År: 1912
Forlag: Seeley, Service & Co. Limited
Sted: London
Sider: 347
UDK: 540 Phi
A Description in non-technical Language of the diverse and wonderful ways in which chemical forces are at work and of their manifold application in modern life.
With 29 illustrations & 15 diagrams.
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PRODUCTION OF LIGHT AND HEAT
When gas (or a candle) bums in the air, the supply of
oxygen is not sufficient for complete combustion of the
carbon and the hydrogen, except in the outermost envelope
of the flame, and the fact that we get any light at all
from an ordinary gas or candle flame is due to a host of
unbumt particles of carbon in the interior. These particles
are raised to a white heat by the
flame, and so make it luminous.
That the ordinary gas or candle
flame contains particles of carbon
may be very easily shown by
holding a cold surface just into
the top of the flame, when a
deposit of soot (that is, carbon in
a finely divided form) is obtained.
|( Q When the supply of air to a
------------gas flame is increased by mixing
/-----------the gas with air just before it
reaches the actual place where
no. 3.—A Bunsen Eurn«. il is burned> then the COmbus-
tion is more complete, the flame
is hotter and no longer luminous. The particles of
carbon which ordinarily make the flame luminous are
now all converted into carbon dioxide, even in the interior
of the flame, by the extra oxygen supplied. This is the
principle of the well-known Bunsen burner, which finds
application now, not only in the laboratory but in our
houses, on incandescent burners and gas stoves.
A simple Bunsen burner is shown in the accompanying
diagram. The current of gas which rushes out at the
central nozzle sucks in air through the surrounding holes
at the bottom of the burner, while the mixture of air
and gas ascends, and is burned at the top of the tube.
112