CHEMICAL PHENOMENA 



57 



Oxygen Silicon 



Phosphorus P Silver 



Platinum Pt Sodium 



Potassium K Sulphur 



Radium Ra Tin 



Si Tungsten 



Ag Uranium 



Na Xenon 



S Zinc 

 Sn 



W 



U 



Xe 



Zn 



Chemical synthesis. We have already learned that 

 if iron filings and sulphur are thoroughly mixed and 

 then heated, a chemical compound, iron sulphide, is 

 formed. When two or more substances combine chem- 

 ically and form a compound, the process is known as 

 chemical synthesis. 



Chemical Analysis. Just as it is possible for sub- 

 stances to combine and form more complex substances, 

 so also, it is possible to decompose these complex sub- 

 stances into the elements of which they are composed. 



Fig. 26. If a glowing pine splinter is inserted into a test tube 

 containing highly heated mercuric oxide, the splinter burns more 

 brightly. 



