13 ANSWERS TO PRACTICAL QUESTIONS 



40. Name the vitriols. 



The compounds of sulphuric acid and oil of vitriol, 

 commonly called " the vitriols," are as follows : 



1. Sulphate of iron, Green vitriol. 



2. Sulphate of copper, Blue vitriol. 



3. Sulphate of zinc, White vitriol. 



41. Is Mg a monad or a dyad ? Zn.? 



Mg belongs to the zinc class of metals which comprises 

 magnesium, zinc, cadmium, and indium. These are all 

 dyads. 



42. Name some dibasic acid. 

 Sulphuric acid, carbonic acid, etc. 



43. Name a neutral salt. An acid salt. 



(See Chemistry, page 128, note.) 



44. Calculate the percentage of water contained in crystal* 

 lized copper sulphate. Sodium sulphate. Calcium sulphate. 

 Alum. 



(i). CuSO, sH.O = 249.5. 



5 H a O = 90. 

 Hence, ,V 9 B = .36 = 36 % of copper sulphate is water. 



(2). Na a SO,, ioH a O = 322. 

 ioH 2 O = 180. 

 Hence, || = .55 = 55 % of sodium sulphate is water. 



(3). CaSO 4 , 2 H a O = 172. 

 2 H 2 O = 36. 

 Hence, r y s = -20 = 20 % of gypsum is water. 



( 4 ). Al a K s , 4 SO 4 + 24H a O = 949. 

 2 4 H 3 O = 432. 

 Hence, -JJf = .45 = 45 % of potash alum is water. 



