CHAPTER II 



COMPOUNDS M IXTURES VALENCE FORMULAS- 

 EQUATIONS 



13. Conservation of Matter. Chemical changes neither 

 create nor destroy matter. By chemical means matter 

 may be converted into new forms having different prop- 

 erties, but the total weight of the substances before chemical 

 action will equal the total weight of the substances after the 



FIG. 5. The black solid, carbon, combined with the yellow solid, 

 sulphur, forms the colorless liquid carbon disulphide. 



action has been completed. Sulphur, when burning, com- 

 bines with the oxygen of the air, and when the sulphur is 

 entirely consumed, the weight of the choking fumes of 

 sulphur dioxide produced will exactly equal the sum of 

 the weights of the sulphur burned and the oxygen with 

 which it combined. 



14. Compounds. Two or more elements when chem- 

 ically combined form compounds. A chemical compound 



13 



