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PRACTICE 4. 

 PREPARATION OF AN AMMONIUM SULFATE SOLUTION. 



Weigh out exactly in a weighed crucible the number of grams of chemi- 

 cally pure ammonium sulfate (assuming the salt to be dry) equivalent to 

 500 cc. of the standard ammonia solution. Dry in the air bath at 115 to 

 120 for thirty minutes, cool in a desiccator, and weigh. Dissolve in am- 

 monia-free water in a 250 cc. measuring flask. Dilute to exactly 250 cc. 

 Mix well, and transfer to a dry 250 cc. bottle. Label and keep stoppered 

 when not in use. 



500 cc. standard NH 3 contains gm. N 



Percent N in (NH 4 ) 2 SO 4 by theory is 



500 cc. NH 3 is equivalent to gm. (NH 4 ) 2 SO 4 



Before After 



ELeating Heating 



Weight of crucible+(NH 4 ) 2 SO 4 = 



Weight of crucible = 



Weight of (NH 4 ) 2 80 4 = 



Percent dry matter in salt is 



How much of the ammonium sulfate will it be necessary to weigh out 

 in order to have exactly 5 gm. of the dry salt? 



