Complete Text (Part 25)

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258 A CORRESPONDENCE COURSE IN PHARMACY If the hydrometer is to be used to find the densities of liquids lighter than water, then the instrument is so made that it descends into the water only to the lower end of the scale. We shall then have the unit at the bottom of the scale and the densities of the lighter liquids graduated above as far as may be necessary. The most common hydrometers are of two kinds — one for densities ranging from 1.000 up to 1.300 and the other for densities ranging from 1.000 down to 0.700. Test Questions 1. Define specific weight. 2. What is the difference between specific weight and specific gravity ? 3. Define specific volume. 4. How are specific weights expressed ? 5. What is the unit of expression for the specific weights of gases ? 6. What is the unit of expression for the specific weights of liquids ? 7. What unit is employed for expressing the specific weights of solids ? 8. What is the quotient obtained when 1 is divided by the specific weight ? 9. What is the quotient obtained when 1 is divided by the specific volume ? 10. What is the specific volume of a liquid the specific weight of which is 1.111 ? 11. What is the specific weight of a liquid the specific volume of which is 1.111 ? 12. What is the product obtained from multiplying the specific volume of a substance by its specific weight ? 13. What practical uses are made of specific weight ? 14. What are the practical uses of specific volume? SPECIFIC WEIGHT AND SPECIFIC VOLUME 259 15. What is meant by commensurate units of weight and volume ? 16. Name several pairs of such units. 17. When it is stated that hydrochloric acid has the specific weight 1.160, what does that number mean ? 18. What is the standard temperature adopted by the pharmacopoeia for finding and expressing specific weights ? 19. Mention a convenient method of taking the specific weight of a fluid extract. 20. Give a method of finding the specific weight of lead. 21. What is a pycnometer ? -" 22. State the law of Archimedes. 23. What are specific gravity beads ? 24. Describe a hydrometer. 25. A piece of metal weighs 8. 3 ounces. The same volume of water weighs 1 ounce. What is the specific weight of the metal ? 26. A bottle holds 480 grains of water, but 576 grains of nitric acid. What is the specific weight of the acid ? 27 If 20 imperial fluid ounces of a liquid weigh 1\ avoir- dupois pounds, what is the specific weight of the liquid ? 28. A one-thousand-grain pycnometer holds 735 grains of ether. What is the specific weight of that ether ? 29. A fluid ounce of alcohol at 22° 0. weighs 373 grains and a fluid ounce of water at the same temperature weighs 455 grains. What is the specific weight of that alcohol referred to water at 22° 0. as unit ? 30. Is the specific weight of that alcohol greater or less referring to water at 15° as unit ? 31. A liter of diluted alcohol weighs 925 grams. What is its specific weight ? 32. A liter of glycerin weighs 1250 grams. What is its specific weight ? 33. A bottle which holds \ ounce of water holds 5 drams 260 A CORRESPONDENCE COURSE IN" PHARMACY of a certain solution. What is the specific weight of that solution ? 34. If 1 gallon of ether and \ gallon of chloroform have the same weight and 2 pints of chloroform weigh the same as 3 pints of water, what is the specific weight of the ether ? 35. I have a solid weighing 13 grams in air. I drop it into a graduated cylinder containing 30 cubic centimeters of water and find that the level of the water rises to 40 cubic centimeters when the solid sinks to the bottom of the cylinder. What is the specific weight of the solid ? 36. The weight of 3 gallons of water is 400 avoirdupois ounces and the weight of a gallon of alcohol is 109 avoir- dupois ounces. What is the specific weight of the alcohol ? 37. An imperial gallon of oil of peppermint weighs 9 avoirdupois pounds. What is its specific weight ? 38. Six pints of solution of zinc chloride weigh 155^- avoirdupois ounces. What is its specific weight ? 39. A mass of thirteen grams of a certain solid has a volume of 10 cubic centimeters. What is its specific weight ? 40. A solid weighs 4.75 grams In air and 4 grams in water. What is its specific weight ? 41. A piece of metal of the bulk of 161.7 cubic inches weighs 347624.55 grains in air and 306839.75 grains in water. What is the weight in grains of 231 cubic inches of water ? 42. A crystal weighs 10 grams in air and 9 grams in oil of turpentine. The specific weight of the oil of turpentine is 0.860. What is the specific weight of the crystal ? 43. One cubic centimeter of a certain solid weighs 870 milligrams. What is its specific weight ? 44. A piece of cork weighs 0.732 grams in air. A piece of metal weighs 7.7 grams in air, but only 6.6 grams in water. Cork and metal tied together and weighed in water are found to weigh 4.182 grams. What is the specific weight of the cork ? SPECIFIC WEIGHT AND SPECIFIC VOLUME 261 45. A piece of lard is put in a vessel of water, and alcohol is gradually added and mixed with the water until the piece of lard instead of floating on the surface may be placed at will in any position in the body of the liquid. A fifty-gram pycnometer is now filled with the liquid and the contents of the pycnometer found to weigh 46.9 grams. What is the specific weight of the lard ? 46. If a piece of metal weighs 9 ounces in air, 8 ounces in water and 8.1 ounces in oil, what is the specific weight of the oil? 47. A solid measuring 10 cubic centimeters when immersed in oil of turpentine is found to displace 8.6 grams of the oil. What is the specific weight of the oil ? 48. Glycerin has the specific volume 0. 800. The weight of three volumes of glycerin is the same as that of five volumes of ether. What is the specific weight of the ether ? 49. Fifty cubic centimeters of nitric acid weigh 71 grams and 50 cubic centimeters of hydrochloric acid weigh 58 grams. The specific weight of the hydrochloric acid is 1.160. What is the specific weight of the nitric acid ? 50. A certain bottle holds 100 ounces of glycerin, the specific weight of which is 1.250. How many ounces of water will it hold ? 51. How much will the same bottle hold of ether having the specific weight 0.720 ? 52. How much will it hold of chloroform of the specific weight 1.470? 53. How much will it hold of syrup having the specific weight 1.330? 54. A solid weighs 3 ounces. It has the specific weight of 8. 300. When weighed in a certain liquid its apparent loss of weight is \ ounce. What is the specific weight of the liquid ? 55. The specific weight of water is 1. What is its specific volume? 262 A CORRESPONDENCE COURSE IN PHARMACY 56. One thousand avoirdupois ounces of a liquid measure 60 pints. What is the specific volume ? 57. If 300 grams of a liquid measure 280 cubic centi- meters, what is its specific volume ? 58. One kilogram of a liquid measures 755 cubic centi- meters. What is the specific volume ? 59. If 4 imperial pints of a liquid weigh 6 pounds, what is its specific volume ? 60. What is the weight of 255 cubic centimeters of a liquid having the specific weight 1.100 ? 61. What is the weight of 30 cubic centimeters of a liquid having the specific weight 0.700 ? 62. What is the weight in avoirdupois ounces of 100 imperial fluid ounces of a liquid having the specific weight 1.960? 63. What is the weight in pounds of an imperial gallon ? 64. What is the weight in avoirdupois ounces of 96 American fluid ounces of a liquid having the specific weight 1.820? 65. What is the weight in avoirdupois ounces of 16 United States fluid ounces of a liquid having the specific weight 1.260? 66. If a cubic inch of water weighs 252.5 grains, what is the weight of 231 cubic inches of a liquid having the specific weight 0.900? 67. If an American fluid ounce of water weighs 0.95 apothecaries' ounce, what is the weight of 1 American fluid ounce of a liquid having the specific weight 0.860 ? 68. What is the volume of 3 kilograms of nitric acid having the specific weight 1.420 ? 69. What is the volume of 5 pounds of a liquid having the specific volume 1.111 ? Give the answer in pints. 70. Castor oil has the specific volume 1.042. What is the volume of 6 pounds stated in American fluid ounces ? SPECIFIC WEIGHT AND SPECIFIC VOLUME 263 71. A piece of metal weighs 6445.380 grains in air. When suspended in water, its apparent weight is 5585.996 grains. Its bulk is 3.40 cubic inches. What is the specific weight of the metal, and what is the weight of a cubic inch of water ? 72. A piece of metal weighs 480 grains in air, 420 grains in water and 400 grains in a solution of sugar. What is the volume of 500 grams of that solution ? 73. A kilogram weight of brass and a kilogram weight of platinum balance each other perfectly in a vacuum. Which has the greater mass ? 74. Which has the greater volume ? 75. Which of them seems to weigh more in air ? 76. You weigh in the usual manner a pound of wood and a pound of lead. Which is really the heavier of the two ? 77. A solid measuring 0.1 cubic decimeter is weighed first in vacuo, then in air, and lastly in water.' One cubic inch of air weighs 0.3 grains and a cubic inch of water 252.50 grains. Find the difference between the weight of that solid in vacuo and its weight in air; the difference between its weight in air and its weight in water. 78. A ten-dollar gold coin weighs 258 grains in air. Assuming its specific weight to be 18.300, what is its apparent loss of weight when weighed suspended in water ? 79. If an imperial gallon of sulphuric acid weighs 18.35 avoirdupois pounds, what is the volume of 1000 grams of that acid expressed in cubic centimeters ? 80. If the specific weight of oil of vitriol be twice that of olive oil, and if 1. liter of olive oil weighs 917. grams, what is the weight of 500 cubic centimeters of oil of vitriol ? 81. If a solid weighs 75 ounces and the same volume of water 10 ounces, what is the apparent weight of that solid when weighed suspended in water ? 82. If a bullet weighs 13 ounces in air and 12 ounces in 264 A CORRESPONDENCE COURSE IN PHARMACY water, what will it appear to weigh in a liquid having 1.400 specific weight ? 83. If a pound of water measure 15f fluid ounces and a pound of a certain solution 7^ fluid ounces, what is the specific volume of the solution ? 84. What number of cubic centimeters expresses the volume of 85.33 grams of a liquid having 1.01 specific volume ? 85. The specific weight of solution of mercury nitrate being 2.100, what is the weight of one liter of it ? 86. Solution of citrate of iron has the specific weight 1.260. What is the weight of one American pint in avoir- dupois ounces ? 87. The specific weight of oil of turpentine is 0.860. What is the weight of 96 American fluid ounces of it in commercial ounces ? 88. Which is greater, the number expressing the specific weight of acetic acid referring to water at 4° 0. as unit, or the number expressing the specific weight of the same acid referring to water at 15° C. as unit ? 89. A certain liquid at 39.2° F. has the specific weight 1.200 referring to water at 22° C. as unit. Will the number expressing its specific weight at 60° F. referring to water at 4° C. as unit be greater or less than 1.200 ? 90. The weight of one liter of water at 4° 0. is 15,432 grains, but the weight of 500 cubic centimeters of water at 22° C. is 7696 grains: (a) What is the specific weight of water at 22° C. referring to water at 4° C. as unit? (b) What is the specific weight of water at 4° C. referring to water at 22° C. as 1 ? 91. An imperial gallon of water at 62° F., barometer at 30 inches, weighs 70,000 grains: (a) Does it weigh more or less at 15° C. ? SPECIFIC WEIGHT AND SPECIFIC VOLUME 265 (b) Does it weigh more or less when the atmospheric pres- sure is greater ? 92. A cubic inch of water at 22° 0. weighs 252.5 grains. What is the weight of 231 cubic inches of an alcohol having 0.860 specific weight, referring to water at 22° C. as 1 ? 93. What is the volume of 100 apothecaries' ounces of oil of 0.900 specific weight, if one cubic inch of water weighs 250.5 grains? 94. What is the specific volume corresponding to each of the following specific weights, respectively: (a) 1.000; (#) 1.250; (c) 1.333; (d) 0.500; (e) 0.750; (/) 0.800; (g) 2.000; (70 0.720; (i) 0.820; (/) 0.950; \k) 1.500; (J) 1.300; (m) 1.320? 95. What is the volume of 1000 grams of a liquid having the specific volume 1.200 ? 96. What is the volume in imperial fluid ounces of 100 avoirdupois ounces of a liquid having the specific volume 0.800? 97. What is the volume in United States fluid ounces of 25 avoirdupois ounces of a liquid having the specific volume 1.000 ? 98. What number of cubic centimeters expresses the volume of 85 grams of a liquid having the specific weight 1.010 ? 99. What number of cubic centimeters expresses the volume of 85 grams of a liquid having the specific volume 1.010? 100. What number of grams expresses the weight of 85 cubic centimeters of a liquid having the specific weight 1.010 ? 101. What number of grams expresses the weight of 85 cubic centimeters of a liquid having the specific volume 1.010? 102. The total weight of a bottle filled with water is 30 266 A CORRESPONDENCE COURSE IN PHARMACY ounces. The same bottle filled with olive oil weighs 28 ounces. What is the weight in ounces of the water the bottle is capable of holding ? How many ounces of oil will it hold ? What is the weight of the bottle itself ? 103. A bottle filled with water weighs 16 ounces ; filled with chloroform having the specific weight 1.470 it weighs 19.877 ounces; filled with acid it weighs 17.32 ounces. How much does it hold of water, of chloroform and of acid, respectively, and what is the specific weight of the acid ? 104. A solid measuring 2 cubic inches weighs 6000 grains in air, but only 5400 grains when weighed suspended in a certain liquid. What is the specific weight of that liquid ? 105. A solid measuring one cubic centimeter and weighing 10 grams loses one gram in weight when weighed in a certain liquid. What is the specific weight of that liquid? 106. Alcohol has the specific weight 0.820 at 15.6° C. The net weight of a barrel of alcohol at that temperature is found to be 300| pounds. How many gallons of the alcohol does that barrel contain ? 107. A certain mixture of water with a syrup of the specific weight 1.330 is found to have the specific weight 1.200. What are the proportions of syrup and water in the mixture ? LESSON EIG-HTEEN XXVII in Pharmaceutical Operations 450. Heat for pharmaceutical purposes may be obtained most conveniently by means of gas burners, but where gas is not available, coal oil and alcohol lamps or burners are used. The Bunsen burner is the most approved gas burner for pharmaceutical and chemical purposes. It is a tube which the gas is mixed with air admitted near the bottom of the \ tube, and the mixture ignited at / i the top. The flame of the gas /A\ ! { burner is bluish when sufficient air is mixed with the gas so that the combustion is complete, but when the gas supply is too abun- dant or the amount of air insuffi- cient, the flame is yellow and deposits unconsumed carbon upon the vessels heated over the flame. 451. The sand bath is an iron dish containing a layer of sand which may be used for the purpose of distributing the heat of the flame. The flask, dish or other vessel to be heated is placed in the sand. A water bath is a vessel of water intervening between the flame and the vessel to be heated. The object of the water bath is to prevent the temperature from rising above the boiling point of water. The contents of vessels heated upon 267 BUNSEN BURNER, CONTRASTING THE PROPER FLAME WITH ONE THAT RESULTS WHEN THE GAS IS "LIGHTED BACK" INTO THE TUBE 2G8 A CORRESPONDENCE COURSE IN PHARMACY the water bath

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