8. 4 litres of hydrogen are passed over heated cupric oxide, what loss of mass does the oxide undergo?

9. Find the mass in grains of a cubic foot of normal hydrogen.

10. Find the mass in grains of a cubic inch of normal hydrogen.

11. 100 grams of levigated iron are dissolved in dilute hydrogen sulphate, what volume of hydrogen at 15° C. is given off?

12.

Fe + H2SO1 = FeSO4 + H ̧.

400 c.c. of hydrogen are measured off at 72° C. and 800 m.m., what is the normal volume ?

13. Find the mass in grams of 10 gallons of hydrogen at 20° C.

14. Find the percentage of hydrogen in (a) hydrogen chloride HCl, (B) hydrogen sulphide H ̧S, (y) ammonia NH,

15. A spherical balloon 50 feet in radius would contain how many pounds of hydrogen and how many pounds. of air?

16. A kilogram of potassium formate when heated with potassium hydrate would give what volume of hydrogen, supposing it were still gaseous, at -140° C. and under a pressure of 494 metres of mercury?

CHKO, + HKO = K ̧CO ̧+ H ̧.

17. How much zinc is required to obtain 100 litres of hydrogen at 91° C. and 800 m.m.?

Zn + H2SO1 = ZnSO1 + H ̧

18. How many c.c. of (a) magnesium (A1·74), (B) zinc (A7-2), (y) iron (A7-8) must be dissolved in acid to give 50 litres of hydrogen at 15° C.?

[MgZnFe] + H,SO1 = [MgZnFe] SO ̧ + H ̧.

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19. 100 grams of potassium formate are heated with potassium hydrate, what volume of hydrogen at 15° C. and 790 m.m. is given off?

20.

The hydrogen used at Woolwich has a lifting power of 71 lbs. per 1000 cubic feet, if the gas were pure what would the lifting power be?

21.

What is the mass of a litre of hydrogen measured over water at 50° C. and 790 m.m.

22. 2 grams of hydrogen mixed with 16 grams of oxygen are exploded in a closed vessel.

Find the pressure

inside the vessel at the moment of explosion.

(The calorific

power of the hydrogen is 34 462, and the specific heat of steam at constant volume is 0·3621.)

23. How much zinc must be dissolved in acid to make 5 cubic metres of hydrogen at 15o C. and 740 m.m.?

Zn + H2SO1 = ZnSO4 + H2.

24. Regnault found that one litre of normal

By dividing by the exact atomic or half molecular weight

determine in each case the mass of a litre of hydrogen, and take the mean of the results.

1. 10 grams of water are decomposed by an electric current, what volumes of hydrogen and of oxygen are evolved?

2. What is the density of hydrogen referred to water? 3. What volume is occupied by 100 grams of steam (HO) measured at 300° C.?

4. 100 c.c. of sodium (A·97) are thrown into water, what volume of hydrogen at 18° C. and 570 m.m. is given off? Na + H2OHNаO + H.

5. How much potassium chlorate must be heated to give oxygen enough to combine with 100 litres of hydrogen? 3H,+30=3H,O.

2

KCIO,= KCl + 30.

6. What volume of oxygen at 12° C. and 762 m.m. is evolved on decomposing 10 grams of water by electricity ? H2O = H2+ 0.

7. What is the volume of 1000 grams of (a) sea-water ▲ 1.026 and (B) ice ▲ ·924?

8. 1000 grams of sea-water (▲ 1·029) contain 35.9 grams of solid matter in solution. How many kilos. of solids are there in solution in a cubic kilometre of sea-water?

9. How many cubic feet are occupied by a ton of seawater (A 1.029)?

10. 400 Troy ounces of water at 16o R. are mixed with 400 avoirdupois ounces at 95° F.

Find the mass of the

mixture in grams and its temperature Centigrade.

11. 500 c.c. of hydrogen at 39° C. are exploded with 500 c.c. of oxygen under a pressure of 332·5 m.m. What volume of which gas is left?

H2+0 = H2O.

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12. How much water must be decomposed by electricity to form one litre of electrolytic gas at 15° C. and 740 m.m.?

13.

H2O=H2+0.

2

2 grams of steam are passed over red-hot iron, what volume of hydrogen at 10o C. and 770 m.m. is formed?

4H2O+3Fe = Fe ̧0, + 4H,.

14. A block of ice (A92) weighs 280 kilos., find its volume.

15. If the density of ice be 0.92, what volume would 1000 c.c. of water at 4° C. occupy when frozen?

16. An iceberg (A ·92) floats in sea-water (A 1·027) with 30 000 cubic metres above the sea, what is the total volume of the berg?

17. Find the density of steam at 300° C. referred to air at 0° C.

18. 1 c.c. of water at 4° C. forms how many times its volume of steam at 300° C. ?

19. The Great Eastern is 679 feet long, 82 feet broad, and 60 feet deep. Find each dimension in metres.

20. 100 grams of steam are passed over red-hot iron, what volume of hydrogen at 14° C. and 730 m.m. is formed? 4H2O+3Fe = Fe ̧0, +4H ̧.

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21. A tube containing cupric oxide, which weighed 105.6 grams, after being heated to redness in a current of hydrogen weighed 101.6 grams. The drying apparatus weighed 80-3 grams before and 84.8 grams after the experiment. How much oxygen unites with 1 part of hydrogen?

h+ 0 = ho.

22. If 88-88 parts of oxygen combine with 11·11 parts of hydrogen to form water, and the equivalent of oxygen be 100, what is the equivalent of hydrogen?

hto = ho.

23. Sea-water (A 1·026) contains 3 per cent. of sodium chloride NaCl; how much sodium is there in a cubic metre of sea-water?

24. 1000 grams of sea-water (A 1·027) contain 37 grams of salt (42.16). What contraction do 1000 c.c. of sea-water undergo during the solution of the salt?

25. If a cubic inch of water at 53° F. weighs 252.765 grains, and 1 c.c. of water at 4° C. weighs 1 gram, what volume will 1 000 000 c.c. of water at 4° C. occupy at 53° F.?

26. In one of Dumas' experiments to ascertain the composition of water by passing hydrogen over heated cupric oxide, the following results were obtained :

grams. Mass of cupric oxide and tube before the experiment 334.598