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23. What volume of carbon dioxide at 76.5° C. is

absorbed in converting 10 kilos. of crystallized sodium carbonate into bicarbonate?

Na,CO210H2O + CO2 = 9H ̧O + 2HNaCO ̧.

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24. What volume of carbon dioxide can be obtained from 3.72 grams of 'bicarbonate of soda' (a) by heating, (B) by the action of an acid?

2HNаCO2 = Na,CO ̧ + H ̧O + CO ̧

HNаCO2+ HCl = NaCl + H2O + CO。.

CHAPTER XXIV.

AMMONIUM. NH1 = 18.

1. A SUBSTANCE contains nitrogen 26-17 per cent., hydrogen 7.48 per cent., and chlorine 66.35 per cent; find its formula.

2.

What is the mass of 4763 c.c. of solution of ammonia (A 0-855) ?

3. 20 grams of ammonium sulphate are heated with lime; what volume of ammonia is given off?

(NH,),SO,+ CaO = CaSO_+ H,O +2NH,

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4. Water at 0° C. absorbs 1000 times its volume of ammonia; what mass of solution of ammonia (NH ̧) can be formed from a litre of water?

5. Find the percentage composition of hydroxylamine NOH,

6. 2 grams of hydroxylamine are heated with solution of potassium hydrate, what volume of nitrogen and of ammonia at 21° C. is formed?

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7. Find the percentage composition of ammonium carbamate (NH ̧),CO,

8. What volume of nitric oxide at 10° C. must be caused to combine with what volume of hydrogen at 20° C. to form 100 grams of hydroxylamine?

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9. Find the formula of a body containing nitrogen 27.45 per cent., hydrogen 9.8 per cent., and sulphur 62.75 per cent.

10. Find the percentage composition of ammonium and hydrogen carbonate (NH),H,3CO..

11. How much ammonium chloride is there in a litre of a solution, 20 c.c. of which, after precipitation with platinum tetrachloride and ignition, gave 0.976 gram of platinum?

2NH Cl+PtCl1 = Pt (NH), Cl,

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Pt(NH), Cl = Pt + 2NH, + 2HCl + 2C1 ̧.

12. How many pints of solution of ammonia (▲ 0·88) weigh 4 lbs?

13. Find the percentage composition of ammonia-alum (NH,),A14SO, . 24H,O.

14. 40 grams of microcosmic salt are heated, how much sodium metaphosphate, what volume of ammonia at 15o C., and what volume of steam at 300° C. is formed?

Na (NH) HPO ̧ . 4H2O = NaPO + NH2+ 5H ̧0.

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How much ammonium chloride must be heated

with lime to make 10 litres of ammonia?

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2NH,Cl + CaO = CaCl,+ H2O + 2HN.

A kilogram of ammonium chloride is heated with lime, what volume of ammonia at 10o C. is given off? 2NH,Cl + CaO = CaCl, + H,O + 2NH,

17. A kilogram of ammonium nitrate is heated, what volume of nitrous oxide at 10° C. is evolved?

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18. A kilogram of ammonium nitrite is heated, what volume of nitrogen at 10° C. is given off?

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19. What volume is occupied by the vapour of 10 grams of ammonium chloride (NHCl) at 350° C. and 700 m.m. ?

20. 10 grams of silver chloride saturated with ammonia are heated, what volume of ammonia at 50° C. is given off?

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21. Water at 15° C. absorbs 740 times its volume of ammonia at the same temperature forming a solution (A 0.855); how much water is there in a litre of such a solution, and how much ammonium chloride is required to make it ?

2NH,C1 + CaO = CaCl, + HgO + 2NH

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22. According to Stas, 100 grams of silver form 157·484 grams of silver nitrate. If Ag=108, and O = 16, find the

atomic weight of nitrogen.

Ag + HNO2 = H+ AgNO ̧.

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CHAPTER XXV.

CALCIUM. Ca = 40.

1. WHAT volume of hydrogen is given off on throwing a gram of calcium into water?

Ca + 2H2O = CaH ̧ ̧ + H ̧.

2. How many grams of chalk must be heated to form a ton of quick-lime?

CaCOg = CaO + CO.

3. 1000 grams of chalk are heated to redness, how much lime is left?

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4. 1000 grams of calcium oxide form how much calcium hydrate?

CaO + H,O = CaH,O..

5. How much calcium is contained in 100 grams of (a) marble CaCO,, (B) gypsum CaSO ̧ . 2H ̧O, (y) fluorspar CaF,, and (8) calcium superphosphate CaH2PO?

6. How many kilograms of calcium hydrate can be obtained by heating 2-726 kilos. of calc-spar to redness and throwing water on the residue ?

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