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113 127 198 56 92 207
7 24 55 200 96 587 94 14 199*2
Silicon. Sodium. Strontium . Sulphur Tantalum . Tellurium. Thallium Thorium Tin . Titanium Tungsten Uranium Vanadium Yttrium Zinc . Zirconium.
23 87'5 32 192 129 204 23195 118
50 184 I 20 513 61.6 65'2 89:6
QUESTIONS AND EXERCISES.
3. (a) How many grams of oxygen can be obtained by heating 1,080 grams of mercuric oxide ?
(6) Twenty-four grams of oxygen are required ; how much mercuric oxide must be heated ?
4. (a) What is left when potassium chlorate is heated ?
(6) How many grams of potassium chlorate must be heated in order to yield 500 grams oxygen ?
(c) How much potassium chloride will remain after heating 247 grams potassium chlorate ?
5. How is potassium chlorate distinguished from potassium chloride?
6. (a) Describe the best means of preparing oxygen ?
(6) The residue in a flask used to prepare oxygen, consisted of 13 grams of potassium chloride; how much chlorate had been heated, and how much oxygen evolved ?
(c) Why is manganese dioxide mixed with potassium chlorate in preparing oxygen ?
8. (a) What happens when a taper is burned in oxygen ?
(6) How is the presence of carbon dioxide generally ascertained ?
9. (a) 14 gram of charcoal containing 96 per cent. of carbon is burnt in oxygen; how much carbon dioxide is produced ?
(6) Contrast the burning of a candle with the breathing of an animal in air.
10. How much oxygen is required to burn 42 grams of sulphur to sulphur dioxide ?
11. How much phosphoric anhydride can be obtained by burning 2*34 grams phosphorus in oxygen, and how much phosphoric acid would be obtained by dissolving the anhydride in water ?
13. (a) How much hydrogen can be got by dissolving 15 ounces of zinc in sulphuric acid ?
(6) Which will yield the greater quantity of hydrogen when dissolved in acids—162 grams zinc, or 140 grams iron? Why?
14. How much water will be formed by burning all the hydrogen evolved by dissolving 342 grams zinc in sulphuric acid ?
15. How much zinc sulphate should be got by dissolving 1 lb. zinc in sulphuric acid ?
19. How is nitrogen prepared ?
21. One hundred grams of potassium nitrate are heated with sulphuric acid ; how much nitric acid and hydrogen potassium sulphate will be obtained ?
88. What are the best tests for nitric acid ?