7. Find the mass in grams of a cubic mile of chalk (A 1.8). 8. A cubic metre of marble (CaCO, ▲ 2·7) contains how many times its volume of gaseous carbon dioxide condensed in it? 9. A litre of water saturated with carbon dioxide dissolves 88 grams of calcium carbonate. How many litres of water are required to dissolve 100 tons of calcium carbonate? 10. A body contains calcium 39.9 per cent., carbon 12.1 per cent., and oxygen 48 per cent. Find its formula. 11. 10 grams of marble are dissolved in hydrogen chloride, what volume of carbon dioxide at 30° C. is given off? 12. CaCO2+ 2HCl = CaCl ̧ + H2O + CO2. 1000 kilograms of limestone are 'burnt', what volume of carbon dioxide at 300° C. is given off? 11.1 CaCO, = CaO + CO. 13. How much calcium sulphate can be formed from grams of calcium chloride? CaCl + H2SO1 = 2HCl + CaSO ̧. 14. How many grams does a pound of selenite lose when heated to 200° C. ? CaSO,2H,O= CaSO, + 2H2O. 15. A substance contains calcium 38.72 per cent., phosphorus 20 per cent., and oxygen 41.28 per cent. Find its formula. 16. 16.44 cent. A salt contains calcium 27.4 per cent., carbon per cent., oxygen 43.84 per cent., and water 12.33 3 per Find its formula. 17. What volume of chlorine at 21° C. must be used to make 1000 grams of bleaching powder, and how much manganese dioxide is required to obtain the chlorine? MnO, + 4HCl = MnCl ̧ + 2H2O + Cl2, 2 18. Calcium hydrate is soluble in 720 times its mass of cold, and in 1300 times its mass of boiling water. How much of the hydrate precipitates on boiling a litre of the saturated solution? 19. How many c.c. of water must be added to 100 grams of plaster of Paris to make it set? CaSO4 + 2H2O = CaSO ̧ . 2H ̧O. 20. How much water do 100 grams of calcium chloride combine with in crystallizing? 21. How many grams of calcium chloride (CaCl2) must be dissolved in a litre of water to be equivalent to a hard water containing x grains of calcium carbonate (CaCO3) per gallon? 22. 1000 grams of sea-water contain 1.33 grams of calcium sulphate, and 0.047 grams of calcium carbonate. How much sea-water would give 3.24 grams of calcium oxalate ? 4 4/2 4 4 CaSO,+(NH,),C,O,= (NH), SO, + CaC,O, 23. 100 grams of bleaching powder are heated with water and cobalt oxide, what volume of oxygen at 21° C. is evolved? 2CaOC1, = 2CaCl ̧ + O̟ ̧. 24. A cistern 10 feet square and 6 feet deep contains water saturated with calcium sulphate, which is soluble in How many kilograms of the 400 times its mass of water. salt are there in the cistern ? 25. 700 c.c. of water dissolve 1 gram of calcium hydrate and 1.26 litres of carbon dioxide. If 700 c.c. of each solution be mixed, what mass of which substance remains in solution? 26. A litre of air at 12° C. when shaken up with limewater gave 0.0017 gram of calcium carbonate. Find the percentage by volume of carbon dioxide in the air. CaH,O, + CO = CaCO. + H,O. 2 2 2 CHAPTER XXVI. STRONTIUM. Sr = 87.6. BARIUM. Ba = 137. 1. FIND the percentage composition of (a) Strontianite SrCO,, (B) Celestine SrSO,, (7) Witherite BaCO2, and (8) Heavy Spar BaSO 2. A strontium (A 2·54) wire 10 c.m. long weighs 2.6 grams, find its radius. 3. What is the probable specific heat of barium? 4. 1000 grams of strontium nitrate are heated, how much strontia is left? Sr2NO2 = SrO + 2NO, + 0. 5. How much baryta can be made from 1000 grams of barium nitrate ? Ba2NO2 = BaO+ 2NO2 + O. 6. 2 grams of strontium are obtained by passing a current of electricity through the fused chloride, what volume of chlorine at 15° C. is set free? SrCl2 = Sr + Cl2. 7. A litre of carbon dioxide at 15° C. is drawn through baryta water; how much barium carbonate precipitates ? HạBaO, + CO, = H,O +BaCO.. 2 2 8. One gram of calcium sulphate will form how much barium sulphate? CaSO+ BaCl, CaCl, + BaSO. 9. 0.591 gram of witherite gave 0·699 gram of barium sulphate; find the percentage of barium in the witherite. BaCO2+ H2SO1 = H2O + CO2+ BaSO 2 2 10. 100 grams of barium monoxide are heated in oxygen, what volume of oxygen at 21° C. is absorbed ? BaO+O=BaO 11. How many cubic metres would a ton of barium sulphate ▲ 46 occupy? 12. 100 grams of water dissolve 5 grams of crystallized barium hydrate, how much hydrogen sulphate is required to precipitate the barium from 20 grams of such a solution? BaH ̧ ̧. 8H2O + H2SO1 = 10H ̧0 + BaSO. 2 2 13. Crystallized barium hydrate (H,BaO,. 8H,O) is soluble in 20 times its mass of cold water. How much barium hydrate is there in 100 grams of the saturated solution? 14. A solution contains 100 grams of crystallized barium chloride per litre, how much hydrogen sulphate will 1 c.c. of the solution precipitate? BaCl,. 2H2O+ H2SO, = 2H2O + 2HCl + BaSO1. 4 15. What volume of sulphur dioxide at 39° C. must be passed over 100 grams of heated barium dioxide to convert it into sulphate? 16. 59 litres of air are drawn over heated baryta, how much barium dioxide is formed? L. C. A. BaO + O = BaO 2° 13 |