92 NON-METALS AND THEIR COMBINATIONS. 



QUESTIONS. 



131. How is sulphur found in nature? 



132. Mention of sulphur: atomic weight, valence, color, odor, taste, 

 solubility, behavior when heated, and allotropic modifications. 



133. State the processes for obtaining sublimed, washed, and precipi- 

 tated sulphur. 



134. State composition and mode of preparing sulphur dioxide and 

 sulphurous acid ; what are they used for, and what are their properties? 



135. Explain the process for the manufacture of sulphuric acid on a 

 large scale. 



136. Mention of sulphuric acid : color, specific gravity, its action on 

 water and organic substances. 



137. Give tests for sulphates and sulphites, sulphuric and sulphurous 

 acid. 



138. What is the difference between sulphates, sulphites, and sul- 

 phides ? 



139. How is hydrosulphuric acid formed in nature, and by what 

 process is it obtained artificially? What are its properties, and what is 

 it used for ? 



140. Mention antidotes in cases of poisoning by sulphuric and hydro- 

 sulphuric acid. 



15. PHOSPHORUS. 



Occurrence in nature. Phosphorus is found in nature chiefly 

 in the form of phosphates of calcium (apatite, phosphorite), iron, 

 and aluminium, and occurs diffused, though generally in small 

 quantities, through all soils upon which plants will grow, as 

 phosphorus is an essential constituent of the food of most 

 plants. Through the plants it enters the animal system, where 

 it is found either in organic compounds, or, and this in, by far, 

 the greater quantity, as tricalcium phosphate principally in the 

 bones, which contain about 60 per cent, of it. From the animal 

 system it is chiefly eliminated by the urine. 



Manufacture of phosphorus. Phosphorus was first made and 

 discovered in 1669 by Brandt, of Hamburg, Germany, a bank- 

 rupt merchant, who obtained it in small quantities by distilling 

 urine previously evaporated and mixed with sand. 



