Page:Outlines of Physical Chemistry - 1899.djvu/185

 chlorine, &c., Berthelot's ' Calorimétrie pratique ' may be consulted with advantage.

In order to make the harmony of the operation and the calculation clearer, I cite an example (taken from the work referred to) :

Combustion of carbon (charcoal purified by chlorine at a red heat).

0*487 gm. charcoal ; ash, 0*0028 gm. ; real carbon, 0*4842 gm.

Preliminary period ; temperatures read :

��After minute 17*360°

After the 1st „ 17-360°

2nd „ 17*360°

Combustion :

After the 5th minute 18-500° 6th „ 18-782°

Final period :

After the 9th minute 18*810° „ 10th „ 18-802° „ 11th „ 18-795°

��After the 3rd minute 17*360° 4th „ 17-360°

��»»

��After the 7th minute 18-820° 8th „ 18-818°

��After the 12th minute 18-785° „ 13th „ 18-775° „ 14th „ 18*770°

Rise in temperature :

Uncorrected : 18-818° - 17-360° = 1-458° Corrected: 1-484°

Water-equivalent of the calorimeter, bomb, compressed oxygen,

thermometer, &c 2,398*4 gm.

Weight of nitric acid formed .... 0*0173 gm.

Total heat observed .... 3,559*2 cal. : of which for the combustion of the iron spiral. 22-4 ) 26 . 3, for the formation of dilute nitric acid . 3*9 '

for the combustion of the carbon. . 3,532*9 cal.

1 gram of carbon evolves 8,136*6 „

12 grams (one gram atomic weight) evolves 97*64 Cal.