32 VETERINARY STATE BOARD 



in nature except in meteoric masses, but is very abundant in certain 

 ores, viz., magnetite, hematite and siderite. 



Give the physical and chemical difference between cast iron and 



wrought iron. 



Cast iron is brittle and cannot be welded or forged. It contains 



two, three or more per cent, of carbon. Wrought iron fuses with 



difficulty and is tough, fibrous and can be welded. It contains 



1.6 per cent, or less of carbon. 



Describe briefly the Bessemer process. 



The Bessemer process of making steel from cast iron, which 

 is accomplished by removing the carbon from the latter, is as follows : 

 melted pig iron (cast iron) is poured into an egg-shaped vessel, 

 called a ' ' converter, ' ' through which a powerful blast of air can be 

 blown. The converter is made of the strongest wrought iron and is 

 lined with an infusible layer of fire clay. As the air bubbles through 

 the molten iron, being forced in from below, the temperature rises 

 and silicon and carbon are burned away. Spiegeleisen is added to 

 supply the proper amount of carbon for good steel. The molten 

 mass is then poured into moulds. 



Mention three important ores of iron. 



Magnetic oxide, Fe304; hematite, Fe^Og-, and siderite, PeCOa. 



Give the common name, the chemical name and the chemical formula of 

 three compounds of iron. 



1. Copperas, or green vitriol, ferrous sulphate, FeS04. 



2. Chloride of iron, ferric chloride, FcjCle. 



3. Carbonate of iron, ferrous carbonate, FeCOj. 



Give the chemical equation showing the preparation of ferrous sulphate. 

 Give the common names of ferrous sulphate and state its 

 uses in medicine. 

 Fe, + 2H,S04 = 2FeS04 + SH^. Fe,S0„7H,0, copperas, green 

 vitriol or ferrous sulphate, is used in medicine as a hematinic, astrin- 

 gent, vermicide and disinfectant. 



What is reduced iron and how is it made? 



It is a very fine, grayish-black, lusterless powder, without odor 

 or taste ; permanent in dry air, insoluble in water or alcohol. 



Made by passing hydrogen gas over freshly made, and carefully 

 washed, ferric oxide, in a hot and closed tube. 



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