QUESTIONS AND PROBLEMS 47 



*48. Determine the co-efficient of solubility of pure salt at 15° C. 



*49. Determine the percentage volume of gas evolved by boiling the tap 

 water. 



*50. Determine the percentage of total solids in the tap water. 



*5i. Percolate 100 grams of the soil with distilled water, previously boiled 

 and cooled, until completely exhausted, and determine the per- 

 centage of soluble matter in the soil. 



Density. 



52. What is meant by "density," and how may it be expressed? "What 



is meant by saying that the " relative density " or specific gravity 

 of brine (saturated at 15° C.) is 1.207? 



53. A bottle holds 28.35 grams of water and 29.30 grams of milk at the 



same temperature. What is the specific gravity of the milk ? 



54. Twenty-five c.c. of a liquid weigh 30.5 grams. What is its relative 



density ? 



55. A piece of glass weighing 25 grams displaces 10 c.c. of water (at 4" C). 



What is the relative density of the glass ? 



56. To what extent does a solid lose weight when immersed in a liquid ? 



If the density of the solid be less than the density of the liquid, will 

 it float or sink ? Try to explain why. 



57. A piece of hard glass weighs 27 grams in air, 16 grams in water, and 



1 1 grams in brine. What is the relative density of the glass and of 

 the brine? 



58. Fully describe the construction of the hydrometer. How can it be 



employed for the determination of the relative density of a liquid, 



and why must the temperature of the liquid be ascertained ? 

 *59. Determine the relative density of the liquid by means of a U tube 



(at W"). 

 *6o. Determine the relative density of the glass, and then, by means of 



the glass, that of the spirit. 



Other Properties of Water. 



61. What is meant by "heat capacity " ? Name the substance which has 



the highest heat capacity of all ordinary solids or liquids. If beakers 

 of water and oil were heated equally, which would become hot the 

 quicker ? When both are hot, which would cool the quicker ? 



62. If I lb. of boiling water be poured into I lb. of water at 15°, the 



temperature of the mixture is found to be 57.5°. If i lb. of boiHng 

 water be poured into i lb. of sand at 15°, the temperature of the 

 mixture is found to be 86°. What is the heat capacity of the sand 

 compared with that of water as unity ? 



