CHAPTER V.

OXYGEN. 0 = 16.

6

N.B. In working the easier sums two volumes' (Sect. 18) are taken as 22.4 litres, and the coefficient of expansion of a gas is taken as 273. In the more difficult sums below the line two volumes are taken as 22.32 litres and 00367 as the coefficient of expansion.

1. 50 grams of potassium chlorate are heated; what mass of oxygen is given off?

2. What volume is occupied by 20 grams of oxygen

(0)?

3.

How much potassium chlorate is required to make 112 litres of oxygen?

4. What volume of oxygen can be obtained from 20 grams of manganese dioxide by heating it (a) alone?

(B) with strong hydrogen sulphate?

MnO, + H2SO1 = MnSO4 + H2O + 0.

5.

What mass of oxygen can be obtained by heating

522 grams of manganese dioxide ?

3MnO1 = Mn2O2+0,

2

3 4

6. How much manganese dioxide is required to make 10 litres of oxygen?

7.

What mass of oxygen (O2) at 10° C. and 750 m.m. would fill a globe of 15 litres capacity?

8. What volume of oxygen can be made from 100 grams of mercuric oxide?

HgO= Hg +0.

9. On heating some potassium chlorate 298 grams of potassium chloride were left. What mass of chlorate was heated and what mass of oxygen was formed?

10.

KCIO1 = KCl + 30.

3

How much potassium chlorate is required to make

70 litres of oxygen?

11.

What volume of oxygen at 21° C. and 380 m.m. can be obtained by heating 1000 grams of potassium chlorate?

12. What mass of oxygen would occupy 13 litres at 12o C.? And how much manganese dioxide must be heated to obtain it?

13. 174 grams of manganese dioxide are heated; what volume of oxygen is given off?

14. How much potassium chlorate will furnish sufficient oxygen to unite with the hydrogen evolved by the action of 200 grams of sodium upon water?

15.

60 grams of mercuric oxide are heated; what volume of oxygen at 91o C. and 380 m.m. is given off?

HgO= Hg + 0.

16. What volume of oxygen can be made from 100 grams of potassium chlorate?

17. A gram of bleaching powder is boiled with water and cupric oxide; what volume of oxygen at 14° C. is given off? CaOCl2 = CaCl, + O.

18. A quantity of barium dioxide is suspended in water and decomposed by carbon dioxide. If 19.7 grams of barium carbonate are formed, what volume of oxygen at 14o C. will be set free on boiling the solution of hydrogen dioxide?

BaO,+CO, + H,O = BaCO, + HẠO,

2

19. 270 grams of mercuric oxide are heated; what volume of oxygen at 0° C. and 760 m.m. is given off? And what will the gas measure at 17° C. and 700 m.m.?

HgO= Hg + 0.

20. What volume of oxygen, supposing that it remained gaseous, at 140° C. and under the pressure of 245.2 metres of mercury, could be made from 613 grams of potassium chlorate?

KCIO,= KCl + 30.

21. If liquid oxygen has the density 89, what would be the volume of the liquefied gas?

22.

What is the mass of 13 litres of oxygen (0) measured at 12° C. ?

23. In one of Dumas and Boussingault's experiments the cupric oxide lost 59.789 grams, and 67.282 grams of water were formed. Calculate the atomic weight of oxygen. CuO+H2 = Cu + H2O.

2

24. 10 grams of potassium dichromate are boiled with hydrogen sulphate; what volume of oxygen at 20° C. is given off?

K ̧Cr2O, + 4H2SO1 = K2SO ̧ + Cr ̧3SO ̧ + 4H ̧O + 30.

2 2 7

4

4

2

25. What volume of liquid oxygen (A·89) could be obtained from 100 litres of the gas measured at 20° C.?

26. What is the mass of 556 c.c. of oxygen (0)1⁄2 measured over water at 20° C. and 750 m.m.?

CHAPTER VI.

HYDROGEN. H = 1.

1. 100 grams of zinc are dissolved in dilute hydrogen sulphate, what volume of hydrogen is given off?

2. What is the mass of 516 litres of hydrogen (H2) measured at -20° C. and 770 m.m.?

3. 100 grams of steam are passed over red-hot iron, what volume of hydrogen at 10° C. and 742 m.m. is formed? 4H,O+3Fe Fe,0, +4H,.

=

4

4. How many litres of hydrogen are obtained on dissolving 16 grams of magnesium in dilute hydrogen sulphate?

5. 50 litres of hydrogen at 17° C. and 800 m.m. are required, how much sodium must be thrown into water?

6. What volume will 1000 c.c. of hydrogen at 0° C.

occupy at (a) 15o C., (B) 100° C., (y) 300° C.?

7. What volume will 1000 c.c. of hydrogen at 100o C. occupy at (a) 0° C., (B) -20° C., (y) - 50° C.?

L. C. A.

8