27. A pound of steam at 374° F. occupies how many cubic feet?

28. 100 grams of gypsum are heated, what volume of steam at 300° C. is given off?

CaSO, 2H,O=CaSO, + 2H2O.

29. 100 grams of each variety of sodium carbonate (i) Na ̧CO,10H ̧0, (ii) Na ̧CO. 8H,O, (iii) Na,CO,. 5H ̧0, (iv) Na,CO. H2O contain how many grams of water?

30. 2 grams of silver oxide are thrown into hydrogen dioxide, what volume of oxygen at 13° C. is given off?

Ag2O+H2O2 = Ag2 + H ̧0 +0 ̧.

2

31. Pure hydrogen dioxide (A1-455) gives how many times its volume of oxygen when boiled?

32. A solution of hydrogen dioxide (A 1-455) gives twenty times its volume of oxygen when boiled, find its percentage composition by volume.

33. What volume of oxygen at 10° C. can be obtained on boiling 10 grams of hydrogen dioxide?

34. 100 grams of solution of hydrogen dioxide in water when boiled gave 5 litres of oxygen at 12o C. and 750 m.m. Find the percentage of hydrogen dioxide in the solution.

CHAPTER VIII.

NITROGEN. N = 14.

WHAT do 100 litres of nitrogen (N.) weigh?

2. 146 litres of nitrogen at 17° C. and 974 m.m. are heated to 51° C. the pressure being decreased to 760 m.m. Find the new volume.

3. What volume of nitrogen can be obtained from 10 grams of ammonium nitrite ?

NH,NO1 = 2H2O+N ̧.

4. 128 grams of ammonium nitrite are heated, what volume of nitrogen at 39o C. and 950 m.m. is given off? NH.NO, 2H,0 + N ̧.

=

5. Find the percentage composition of ammonium nitrate NH.NO.

6. What volume is occupied by 10 000 grams of hy-. drogen nitrate (A 1.5)?

7.

What volume of nitrous oxide can be obtained from 240 grams of ammonium nitrate ?

8. How many pounds of hydrogen nitrate are obtained on distilling 400 pounds of sodium nitrate with hydrogen sulphate?

2NaNO3 + H2SO, Na,SO, + 2HNO,.

=

9. What volume of nitric oxide is obtained on dissolving 10 grams of copper in hydrogen nitrate?

3Cu + 8HNO2 = 3Cu2NO ̧+ 4H ̧0 + 2NO.

2

10. What volume of nitric oxide at 13° C. is obtained on dissolving 25 grams of copper in hydrogen nitrate?

3Cu + 8HNO1 = 3Cu2NO, + 4H2O + 2NO.

2

11. How much copper is required to form 10 litres of nitric oxide?

3Cu+8HNO1 = 3Cu2NO2+ 4H ̧0 + 2NO.

12. How much ammonium nitrate is required to make 40 litres of nitrous oxide?

13. 30 c.c. of nitrogen at 18° C. were measured in a tube. The barometer was 750 m.m. and the mercury stood at 120 m.m. in the tube. Find the normal volume of the gas and its mass in grams.

14. 127 grams of copper are dissolved in hydrogen nitrate, what volume of nitric oxide at 14° C. and 1000 m.m. is given off?

3Cu+8HNO, 3Cu2NO, + 4H2O+2NO.

=

15. What volume of hydrogen sulphate (A 1·84) must be distilled with 1 kilo. of sodium nitrate to make hydrogen nitrate, and what volume of hydrogen nitrate (A 1·5) will be formed?

NaNO + H2SO HNASO + HNO,.

3

=3 4

16. What is the mass of 100 litres of (a) nitrous oxide NO, and (B) nitric oxide NO?

17. What volume of nitric oxide is obtained on boiling 50 grams of hydrogen nitrate with an excess of acidified ferrous sulphate ?

2HNO, +3H,SO, + 6FeSO, 3Fe,3SO, + 4H,O+ 2NO.

=

18.

What is the mass of 270 c.c. of nitrogen measured over water at 8° C. and 768 m.m.?

19. How much phosphorus can be burnt in 4 litres of nitrous oxide measured at 14° C.?

20.

5 c.c. of mercury (▲ 13.55) are warmed with hydrogen nitrate, what volume of nitric oxide at 21° C. is evolved?

3Hg+8HNO2 = 3Hg2NO2+4H2O +2NO.

21. 100 grams of cuprous oxide are warmed with dilute hydrogen nitrate, what volume of nitric oxide is evolved?

3Cu ̧0 +14HNO, = 6Cu2NO, + 7H ̧0 + 2NO.

2

2

22. At 27° C. nitrogen tetroxide is 2·65 times as heavy as air, and at 180° C. it is 1.57 times as heavy, find the corresponding molecular weights.

23. Find the percentage composition of (a) nitrosyl chloride NOCI, and (B) nitryl chloride NO,Cl.

24. What volume of chlorine at 15o C. must be passed over 20 grams of silver nitrate to obtain nitrogen pentoxide? C1, + 2AgNO ̧= 2AgCl + O + N ̧O

25. 4 litres of nitric oxide at 17° C. and 750 m.m. are passed over red-hot copper, what volume of nitrogen at 7o C.

and 600 m.m. is formed?

2NO + 2Cu = 2CuO + N ̧

2°

26. 3 grams of urea are warmed with potassium nitrite and hydrogen sulphate, what volume of nitrogen and of carbon dioxide is given off?

CON ̧Í ̧ + N ̧O̟ ̧ = 2N ̧+ 2H ̧O + CO ̧

2

27. 300 grams of dry lead nitrate are heated, what volume of nitrogen tetroxide at 100° C. is evolved?

28. Excess of carbon is thrown into 100 grams of fused potassium nitrate, what volume of nitrogen and of carbon dioxide is evolved?

4KNO, + 5C = 2K ̧CO2 + 2N ̧ + 3CO,

30. What volume of ammonia is required to neutralize 10 grams of hydrogen chloride?

31. What volume of ammonia at 15° C. and 740 m.m. could be obtained from 107 grams of ammonium chloride?

32.

2NH,Cl + CaO = CaCl, + H,O + 2NH.

What is the mass of 2 litres of solution of ammonia (A .88)?

33. What volume is occupied by 100 grams of ammonia NH,?

34. 29 c.c. of ammonia are decomposed by a series of electric sparks, and the mixed gases are exploded with 30 c.c. of oxygen. What volumes of what gases remain ?