124 AGRICULTURAL CHEMISTRY 



150. A Knowledge of Reacting Compounds and Prod- 

 ucts Necessary. In order that the writing of chemical 

 equations may become more than a mere mechanical op- 

 eration, the student should study the character and prop- 

 erties of the compounds used and of the products formed . 

 If one of the compounds is an acid and the other a base, 

 the subject of neutralization is illustrated. If one of the 

 compounds is an acid and the other a metal, the re- 

 placement of the H of the acid occurs. Should one of 

 the compounds be an acid and the other a salt, an equiva- 

 lent amount of the H is replaced by the metal or basic 

 element of the salt. Other principles and laws should 

 be observed by the student in writing equations. The 

 character of the compounds, as acid, base, or salt, with 

 their names, forms a part of equation work, which is an 

 essential feature of elementary chemistry. 



151. Equations for Class Room Work. The student 

 should write the following equations : 



1. CaCl 2 + Na 2 CO 3 = 



2. CaCl a + Na 2 SO 4 = 

 3. 



4. 

 5. 

 6. 

 7. 



8. Pb(N0 3 ) 2 + 2HC1 = 



9. A1C1 3 -f NH 4 OH = 



10. Ba(OH) 2 + H 2 SO 4 = 



11. BaCl 2 + H 2 SO 4 = 

 12. 



