96 CYANAMID — MANUFACTURE), CHEMISTRY AND USES 



nitrogen content of each filtrate was determined with the fol- 

 lowing results : 



Sample Grams of Grams of Per cent, of 



grams N. in sample N. in filtrate total N. in filtrate 



1 0.1358 0.1227 90-4 



2 0.2716 0.2357 86.8 



4 0.5432 0.4729 87.1 



8 1.0864 0.8103 74.6 



EXPERIMENT n. 

 Solubility in Flasks. — Samples of 2, 4, 8, 17 and 32 grams 

 of granulated Cyanamid were placed in Erlenmeyer flasks and 

 each covered with 400 cc. of distilled water at 25° C. The 

 flasks were stoppered, and allowed to stand 24 hours, with 

 occasional shaking. They were filtered through dry filters 

 without washing and nitrogen was determined in each filtrate, 

 with the following results : 



Sample Grams of Grams of Per cent, of 



grams N. in sample N. in filtrate total N. in fillrate 



2 0.2716 0,2548 93.9 



4 0.5432 0.5102 93.9 



8 1.0864 1.0119 93.1 



16 2.1728 2.0087 92.5 



32 4.3456 3-9588 91. 1 



EXPERIMENT HI. 

 Rate of Solution in Flasks. — In each of five flasks was placed 

 2 grams of granulated Cyanamid and 250 cc. distilled water at 

 25° C. Each flask was shaken for 10 minutes continuously, 

 after addition of the sample, and then only occasionally. After 

 filtration without washing, nitrogen was determined in the 

 filtrate. The following results were obtained: 



Gram of Gram of Per cent, of 



Time N. in sample N. in filtrate total N. dissolved 



10 minutes 0.2716 0.2055 75-6 



30 ** 0.2716 0.2298 84.6 



2 hours 0.2716 0.2403 88.5 



6 *' 0.2716 0.2433 89.6 



24 " 0.2716 0.2480 91.3 



Neutral Permanganate Method. — One of the permanganate 

 availability methods formerly much used is the neutral 



