144 SPECIFIC GRAVITY. 



33. A certain body weighs just 10 g. It is placed in one of the 

 scale-pans of a balance together with a flask full of pure water. 

 The given body and the filled flask are counterpoised with shot in 

 the other scale-pan. The flask is removed, and the given body 

 placed therein, thus displacing some of the water. The flask being 

 still quite full is carefully wiped and returned to the scale-pan, 

 when it is found that there is not equilibrium. To restore the 

 equilibrium, it is necessary to place 2.5 g. with the flask. Find the 

 specific gravity of the given body. 



34. The volume of the earth is 1,062,842,000,000,000 cu. Km. 

 Calculate its weight on the supposition that its average density is 

 5.6604. 



35. A bottle holds 2545 mg. of alcohol (sp. gr. = 0.8095); 42740 

 mg. of mercury ; 5829 mg. of sulphuric acid. Calculate the specific 

 gravities of the mercury and of the acid. 



36. A piece of cork weighing 2.3 g. was attached to a piece of 

 iron weighing 38.9 g., both were found to weigh in water 26.2 g., the 

 iron alone weighing 33.9 g. in water. Required the specific gravity 

 of the cork. 



37. A piece of wood weighing 300 grs. has tied to it a piece of 

 lead weighing 600 grs.; weighed together in water they weigh 472.5 

 grs. The specific gravity of lead being 11.35, (a) what does the lead 

 weigh in water ; (&) what is the specific gravity of the wood? 



38. Calculate the specific gravity of a mineral water from the 

 following data : 



Weight of a bottle empty 14.1256 g. 



" filled with distilled water. .111. 1370 g. 

 " " " " mineral " ..111. 7050 g. 



39. A Fahrenheit's hydrometer weighs 618 grs. It requires 93 grs. 

 in the pan to sink it to a certain mark on the stem. When wiped 

 dry and placed in olive oil it requires only 31 grs. to sink it to the 

 same mark. Find the specific gravity of the oil. 



40. A platinum ball weighs 330 g. in air, 315 g. in water and 303 g. 

 in sulphuric acid. Find the specific gravities (a) of the ball ; (b) of 

 the acid, (c.) What is the volume of the ball ? 



41. A hollow ball of iron weighs 1 Kg. What must be its least 

 volume to float on water ? 



42. A piece of cork weighing 30 g. in air, was attached to 10 cu. 

 cm. of lead. Loss of both in water = 159 g. Required the specific 

 gravity of the cork. 



43. A body whose specific gravity = 2.8, weighs 37 g. Required 

 its weight in water. 



