NAME DENSITY COMPOSITION BY PERCENTAGE Hydrosulphuric acid 1.1791 S = 94.11 H = 5.89 Sulphur dioxide 2.222 S = 50.05 O = 49.95 Sulphur trioxide 2.74 S = 40.05 O = 59.95 Sulphur chloride 4.70 S = 47.48 Cl = 52.52 Sulphuryl chloride 4.64 S = 23.75 Cl = 52.53 O = 23.70 Carbon disulphide 2.68 S = 84.24 C = 15.76 2. Calculate the formulas for compounds of the following compositions: MOLECULAR WEIGHT (1) S = 39.07% O = 58.49% H = 2.44% 81.0 (2) Ca = 29.40 S = 23.56 O = 47.04 136.2 (3) K = 38.67 N = 13.88 O = 47.45 101.2 3. The molecular weight of ammonia is 17.06; of sulphur dioxide is 64.06; of chlorine is 70.9. From the molecular weight calculate the weight of 1 l. of each of these gases. Compare your results with the table on the back cover of the book. 4. From the molecular weight of the same gases calculate the density of each, referred to air as a standard. 5. A mixture of 50 cc. of carbon monoxide and 50 cc. of oxygen was exploded in a eudiometer, (a) What gases remained in the tube after the explosion? (b) What was the volume of each? 6. In what proportion must acetylene and oxygen be mixed to produce the greatest explosion? 7. Solve Problem 18, Chapter XVII, without using molecular weights. Compare your results. 8. Solve Problem 10, Chapter XVIII, without using molecular weights. Compare your results. 9. The specific heat of aluminium is 0.214; of lead is 0.031. From these specific heats calculate the atomic weights of each of the elements. CHAPTER XX THE PHOSPHORUS FAMILY ================================================== | | ATOMIC | | MELTING | SYMBOL | WEIGHT | DENSITY | POINT -----------+--------+---------+---------+--------- Phosphorus | P | 31.0 | 1.8 | 43.3 deg. Arsenic | As | 75.0 | 5.73 | --- Antimony | Sb | 120.2 | 6.7 | 432 deg. Bismuth | Bi | 208.5 | 9.8 | 270 deg. ================================================== ~The family.~ The elements constituting this family belong in the same group with nitrogen and therefore resemble it in a general way. They exhibit a regular gradation of physical properties, as is shown in the above table. The same general gradation is also found in their chemical properties, phosphorus being an acid-forming element, while bismuth is essentially a metal. The other two elements are intermediate in properties. ~Compounds.~ In general the elements of the family form compounds having similar composition, as is shown in the following table: