Mixter — Formation of the Oxides of Molybdenum, etc. 489 



The results of burning the metal with sodium peroxide are 

 as follows : 



Molybdenum .__ * 



Sodium peroxide 



Water equivalent of system . 

 Temperature interval 



V'000 grams 

 25* 



7-000 grams 

 25* 



,960* 



3-803° 



u 



4,047* 



3-720° 



15,060° 



— 48° 





15,055° 



— 48° 



— 31° 





— 52° 



Heat effect 



" of oxidation of iron . 

 " " oxygen absorbed . 



14,981° 14,955° 



For 1 gram of molybdenum. _ 2,140° 2,136° 



The mean is 2,138 and for 96 grams of molybdenum it is 205,248°. 



From this result and the heat of union of sodium oxide with 

 molybdenum trioxide found in experiments 3, 4, and 5, the 

 heat of oxidation of molybdenum to the trioxide is derived as 

 follows : 



3Na 2 2 + Mo = Na 2 Mo0 4 + 2Na 2 + 205-2 



3Na 2 + 30 = 3Ka 2 2 + -- 58-2 



NaO + Mo + 30 = NaMoO, + 263*4 



JSTaO + MoO, = NaMo0 4 + 81-9 



Mo + 30 = Mo0 3 + 181-5° 



Molybdenum trioxide used in the following experiments 

 was heated in a porcelain crucible to expel moisture, allowed 

 to cool in a desiccator and weighed. Sulphur or acetylene 

 carbon was added to the mixture of the trioxide and sodium 

 dioxide to reduce the latter to oxide and also to furnish heat 

 necessary for fusion. It will be observed that where carbon 

 was used the amount of oxygen evolved was large although 

 sodium oxide was formed in excess of the amount equivalent 

 to the molybdenum trioxide. The following are the experi- 

 mental results : 



3 4 5 



Molybdenum trioxide 7*501 gr. 5-115 gr. 8-140 gr. 



Carbon... 0*618 " 0*546 " 



Sulphur. __ 2-000" 



Sodium peroxide. 17' " 12* " 21* " 



Water equivalent of system 4,164* "4,018* "4,196* " 



Temperature interval 2*515° 2*145° 3616° 



