QUESTIONS AND ANSWERS 23 



the air enters are stopped up, the flame becomes more luminous and 

 less hot. 



Give proof of the fact that a diamond is composed of carbon. 



A diamond, when heated intensely in the presence of oXygen, 

 burns and forms carbon dioxide. 



SULPHUR 



Mention the properties and important uses of sulphur. 



Sulphur is ordinarily a yellow, brittle soUd, without taste or 

 odor. It dissolves in carbon disulphide, but not in water, and 

 combines easily with most of the other elements. Allotropic forms : 

 prismatic or monoclinic, rhombic octahedra, and plastic. Uses: 

 Used in the manufacture offSpowder, matches, suTpKuric acid, 

 bleaching agents, in medicine, etc. 



Discuss the behavior of sulphur at different temperatures. 



At 115° C. it melts to a clear, amber-colored liquid which be- 

 comes viscid as the temperature rises to 230° C. Above 250° C. it 

 becomes fluid again and if poured into cold water it becomes plastic 

 or ductile, but after standing a few days it returns to its primary 

 condition, original sulphur. 



Describe the use of sulphur in disinfecting. Explain its efficiency. 



Remove animals from premises. All openings to outside air 

 should be closed. Three pounds of flowers of sulphur, mixed with 

 two ounces of alcohol and ignited, should be employed for every 

 1000 cubic feet of air space to be disinfected. Keep premises 

 closed for six hours. Steam introduced into the apartment together 

 with the sulphur fumes is more efficient, the water unites with the 

 sulphurous anhydride to make the more potent sulphurous acid 

 (HjSOg). Sulphur fumigation is of little worth to destroy disease 

 germs. Formaldehyde or chlorine gas is to be preferred. 



Write the formula of hydrogen sulphide. Describe its properties. 



HjS. A colorless gas with the peculiar odor of rotten eggs 

 and a disgusting taste. It is soluble in water and highly combustible 

 in the air, burning with a blue flame and forming sulphur dioxide 

 and water. This gas is poisonous when inhaled. 



Describe a method of preparing hydrogen sulphide. 



Prepared by the action of dilute sulphuric acid upon iron 

 sulphide. (PeS + H,SO, = FeSO, + H,S. ) 



Describe a process of preparing sulphuric acid on a commercial scale. 

 Mention the important uses of sulphuric acid. 

 "Lead chamber process." Sulphur dioxide, generated by the 



