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Part II 

 (Answer five questions from Part 11. Extra questions will receive no credit.) 



6. Explain each of the following facts: 



a) Painters' rags sometimes take fire spontaneously. 



b) Concentrated rather than dilute sulphuric acid is used in making hydro- 



chloric acid. 



c) Acetic and nitric acid solutions of the same concentration in gram mole- 



cules per liter do not conduct electricity equally well. 



d) When the stopper is removed from a bottle containing concentrated hydro- 



chloric acid, white fumes are sometimes observed. 



e) A solution of sodiiun carbonate has an alkaUne reaction. 



7. Indicate the difference in meaning between (a) ion and radical, (J) electrolysis 



and ionization, (c) equivalent and atomic weight of an element, {d) hydrate 

 and hydroxide, (e) monobasic and dibasic acid. Give an example of each, 



8. A portable gas stove used in heating a room burns natural gas (assumed to be 



pure methane, CH4) and consumes in one hour 10 cubic feet of gas measured 

 at a pressure of 30 inches of mercury and at a temperature of 60° F. What 

 volume of oxygen is consumed and what space is occupied by the carbon 

 dioxide which is produced, when measured under conditions of pressure 

 and temperature previously specified ? If 1 cubic foot of methane under 

 these conditions weighs 0.04225 lbs., what weight of water vapor is formed 

 during the combustion ? (O 16, C 12, HI.) 



9. State one practical use for each of the following substances, suggested by the 



property mentioned. Give in each case an example of such a substance, 

 (a) A metal having a very high melting-point, {b) a substance from which 

 a water solution having a very low freezing-point may be made, (c) an acid 

 having a high boiling-point, {d) a solid or liquid capable of sudden conversion 

 into gases at high temperature, ie) a volatile, non-inflammable liquid. 



10. How could you obtain (a) sulphur from hydrogen sulphide, {b) metallic 



copper from copper oxide, (c) potassium nitrate crystals from potassium 

 chloride, id) ferric oxide from ferric chloride ? 



11. Two gram molecules of the oxide RO combine with 44.8 liters of oxygen at 



0° and 380 mm. pressure. The volume of the product, under the same 

 conditions, is nearly equal to that of the oxygen taken. Calculate the 

 formula of the product. 



12. a) Name the products when: silica is fused with sodium carbonate; when 



dilute sulphuric acid acts on magnesium. 



b) Give two uses for each of the following substances: ammonium hydroxide, 



borax. 



c) Why is nitric acid a better solvent for silver, lead, and mercury than hydro- 



chloric acid ? 



(THIS EXAMINATION IS CONTINUED ON PAGE 3) 



