Part II 

 (Answer five questions from Part II. Extra questions will receive no credit.) 



6. a) What is a normal solution of an acid ? of an alkali ? 



b) 10 c.c. of ordinary household ammonia are neutralized by the addition of 

 40 c.c. of a normal solution of hydrochloric acid. What weight of 

 ammonia gas, NH3, is contained in each cubic centimeter of the original 

 solution ? 



7. Discuss {a) the extraction of sulphur in the United States and abroad; {b) its 



physical and chemical properties; (c) its uses. 



8. a) Give an example of a chemical change brought about by heat, another by 



light, and a third by electricity. Mention three chemical reactions the 

 first of which produces heat, the second light, and the third electricity. 

 b) Distinguish between exothermic and endothermic reactions and illustrate 

 each by means of an example. 



9. 1 .8 grams of magnesium displace from acid 1820 c.c. of hydrogen, measured 



dry at 740 mm. pressure and 20° C. Find the volume of this gas under 

 standard conditions and determine the valence of magnesium. (Mg. = 24 . 3, 

 H = 1 . 008.) What is your definition of valence ? 



Note — The weight of one liter of hydrogen under standard conditions is 0.09 gram. 



10. a) What is an electrolyte ? Distinguish between electrolysis and electrolytic 



dissociation. 



6) If a strong (active) acid is added to the salt of a weak acid in water solution, 

 what becomes of the four different ions involved ? Illustrate by an 

 example. 



11. Describe the manufacture of any one of the following substances, giving a 



diagram, and equations whenever possible: (a) Ethyl alcohol; {b) water 

 gas; (c) open-hearth steel. 



12. a) What danger is there in a long-continued scarcity of potassium compounds ? 



Why has there recently been such a scarcity in this country ? 

 b) Make a list of the sources of potassium compounds. Suggest a method for 

 extracting a potassium compound from two of the raw materials men- 

 tioned. 



13. a) Outline a commercial method for producing metallic aluminium, {b) How 



is aluminium used to produce other metals from their oxides ? (c) Ex- 

 plain the fact that aluminium retains its bright appearance in the air. 

 {d) Mention one industrial use for alum. 



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