PHILIPPINE COALS AS FUEL. 



347 



The introduction of an inert gas such as the nitrogen content of the combus- 

 tion chamber, greatly raises the ignition temperature and for tlie bimolecular 

 reaction between hydrogen and oxygen it is increased according to tlie equation 



where 



T=T'+30 n 

 volume of the nitrogen (Nj) 



volume of the hydrogen (H,) or the oxygen (O2) 



whichever is present in the smallest quantity. For the trimolecular reaction 

 between carbon monoxide and oxygen the ignition temperature is increased 

 .according to the equation T=T'+80 n' where 



volume of the nitrogen (Nj) 



volume of the carbon monoxide (CO) 



The temperature coefficient of the reaction velocities for an increase of 10° 

 is L31 between the limits 514° and 550° for a mixture of hydrogen and oxygen; 

 and 1.24 between the limits 601° and 645° for a mixtiire of carbon monoxide and 

 oxygen. The introduction of an indifferent gas (nitrogen) reduces the magnitude 

 of this coefficient in proportion to the quantity added. 



For a mixture of two volumes of carbon monoxide and one volume of oxygen 

 Helier " gives the following maximum formation of carbon dioxide, expresed in 

 per cent at the given temperature: 



Degrees 

 centigrade. 



Per cent 

 CO 2 



Degrees 

 centigrade. 



Per cent 

 CO 2 



195 



0.13 



504 



7.3 



302 



0.44 



566 



14.43 



365 



1.41 



575 



17.27 



408 



3.03 



600 



21, 14 



418 



3.41 



689 



43.36 



468 



4.64 



788 



60.3 



500 



6.2 



855 



65.0 



The formation of carbon dioxide from the carbon compounds in coal or even 

 by burning carbon monoxide itself is no simple one. The dissociation of carbon 

 dioxide into carbon monoxide and oxygen and the part that water plays in the 

 reaction must all be considered. A perfectly dry mixture of carbon monoxide 

 and o.xygen can neither be exploded by means of a red glowing platinum spiral 

 nor an induction spark.™ The particles of water themselves play an important 

 part in the reaction. Even at ordinary temperatures there is a small amount 

 of free hydrogen and free oxygen in water vapor. The equilibrium at 10° 

 contains one volume of free hydrogen and one-half volume of free oxygen for 

 every 4.55 . 10°' volumes of water vapor. The higher the temperature the greater 

 the amount of uncombined gases in proportion to water vapor. When the 

 equilibrium is reached at 100° there is one volume of free hydrogen and one- 

 half volume of free oxygen for each 1.14.10" volumes of undissooiated water 

 vapor.^' At very high temperatures free hydrogen and oxj'gen are present in 

 such quantities that they may be directly determined. These free gases are 

 chemically very much more active than the water molecules themselves. The 



"A«». de Chim. (1897) (7), 10, 521; Chem. Centril. (1897) I, 68, 487. 

 ^"Bixon, Chem. News (1S82), 46, 151. 

 ''Bodlander: Ahren's Samtn. chem. u. chem. tech. Vortrdge (1899), 3, 388. 



