18 Preparation of Substances 



neutralized solution in colloidal condition 

 and are not flocculated until the ammonium 

 sulfate solution has become more concen- 

 trated. Should flocculation occur during the 

 course of evaporation the tarry substance 

 then may be filterd out. It is this material 

 left in the preparation which gives the pecu- 

 liar brownish color to commercial sulfate of 

 ammonia. 



The point of crystallization is determind 

 by blowing across the surface of the hot 

 liquid. When a scima appears at once the 

 evaporation by flame may cease. 



QUESTIONS 

 (To be answerd in the notebook.) 



1. How many grams of amimonia in 2 kilos of a solu- 

 tion containing 28.33%? 



2. How much ammonia in 250 cc. of a solution of a 

 sp. gr. of 0.970 containing 7.31% of NH3? 



3. How many tons of ammonium sulfate could be 

 made from a tank car of concentrated ammonia con- 

 taining 5000 gallons of 14% NH3? The weight of a 

 gallon may be taken as 8 pounds. What is this worth 

 at $60.00 per ton? 



4. What is the per cent of ammonia in ammonium 

 sulfate? 



5. Write the reactions, giving] the names, showing 

 how two different salts may be made by putting to- 

 gether ammonium hydroxid and sulfuric acid. 



6. What other substances in addition to ammonia 

 are produced by distilling soft coal? 



