47. 390 grams of antimony sulphide are dissolved in hot hydrogen chloride, what volume of hydrogen sulphide at 30° C. is given off?

48.

Sb,S2+6HCl = 2SbCl ̧ + 3H ̧S.

How many grams of sulphur are there in 600 c.c. of hydrogen sulphide (H,S)?

49.

Find the mass of a roll of brimstone (A 2) 1 m. long and 4 cm. in diameter.

50.

10 grams of carbon disulphide (CS,) vapour occupy what volume at 210° C. ?

51. Find the percentage composition of sodium thiosulphate (Na,S,O ̧ . 5H ̧0).

52. What volume of chlorine at 15° C. and 720 m.m. must be passed into excess of melted sulphur to make 245 grams of sulphur monochloride?

53.

What volume of air is required to burn 1000 grams

of sulphur?

S+O2 = SO,.

54. 2.867 grams of sulphur are burnt, what volume of sulphur dioxide at 30° C. is formed?

55.

What is the density of hydrogen sulphide (H,S)

referred to air?

56. What is the mass of 4 litres of carbon oxysulphide (COS) at 30° C. ?

57. A cubic decimetre of ferrous sulphide (A 4.4) is dissolved in dilute acid, what volume of hydrogen sulphide at 17° C. and 770 m.m. is given off?

58. What volume would the vapour of 10 grams of hydrogen sulphate (H2SO) occupy at 400° C. ?

59. What volume of nitric oxide is required to burn 10 grams of carbon disulphide?

CS, + 6NO = 6N + CO2 + 2SO。.

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60. If 134 grams of antimony sulphide are dissolved in hot hydrogen chloride, what volume of hydrogen sulphide at 15° C. is given off?

61. A room 5 by 4 by 5 metres, the air of which contains 20 per cent. by volume of available oxygen, is to be disinfected. What volume of carbon disulphide (▲ 1·2) can be burnt in it?

62. What volume of carbon disulphide (A 1.27) must be burnt to give 10 litres of sulphur dioxide at 15o C., and 750 m.m.?

63. 100 grams of mercury are heated with hydrogen sulphate, what volume of sulphur dioxide at 30° C. and 800 m.m. is given off?

64. 10 litres of hydrogen sulphide at 15o C. are passed into antimony trichloride, how much antimony trisulphide precipitates?

3H,S+2SbCl2 = 6HCl, + Sb2S ̧.

65. To make 1000 kilos. of hydrogen sulphate, how much pyrites, what volume of air at 15o C., and what volume of steam at 300° C. is required?

2FeS ̧ + 4H2O +150 = Fe ̧ ̧ + 4H2SO.

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CHAPTER XVI.

BORON. B=11.

1. FIND the formula of substances containing (a) boron 31.19 per cent., and oxygen 68.81 per cent., (B) silicon 46.6 per cent., and oxygen 53.3 per cent.

2. Find the percentage composition of borax (Na,BO, 10H 0).

3. Boron trichloride is 4·07 times as heavy as air, what is its molecular weight?

4. What volume of boron trichloride at 210° C. can be made from 390 grams of boron trioxide?

5.

What volume of nitrogen at 15° C. is required to convert 4.4 grams of boron into boron nitride?

B+N=BN.

6. 7 grams of boron nitride are heated in a current of steam, what volume of ammonia at 13o C. is given off?

2BN + 3H,0=B2O2+2NH ̧.

7. 10 grams of boron sulphide are heated in steam, what volume of hydrogen sulphide at 21° C. is formed?

8. Crystallized hydrogen borate when heated to 100° C. loses 21.8 per cent. of water, and when heated to 160o C. loses 14.5 per cent. in addition. Find the formulæ of the bodies formed.

(B2O2), (H ̧O)2 = (B ̧0 ̧), (H2O)1⁄2- ̧ +(H2O)..

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9. Find the percentage composition of boron and nitryl chloride (BNOCI).

10. 90 grams of fluorspar are heated with boron trioxide and hydrogen sulphate, what volume of boron trifluoride at 15° C. is formed?

3CaF, + B2O2+3H2SO1 = 3CaSO + 3H ̧0 + 2BF ̧.

2

2

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11. How much does a litre of boron fluoride (BF) measured at 50° C., and 1000 m.m. weigh?

12. A substance contains nitrogen 14.68 per cent., hydrogen 3.15 per cent., boron 7.69 per cent., and chlorine 74.47 per cent., find its formula.

13. What volume of ammonia gas at 10°C. is required to convert 10 grams of boron into the nitride?

2B + 2NH ̧ = 3H ̧ + 2BN.

CHAPTER XVII.

SILICON. Si = 28.

1. How much silicon can be obtained from 119 grams of potassium silicofluoride?

K2SiF+4K = 6KF + Si.

2. Find the percentage composition of barium silicofluoride BaSiF..

3. Two litres of the vapour of silicon chloride at 117°C. are passed over heated sodium, how much silicon is formed? SiCl + 4Na = 4NaCl + Si.

4. Find the percentage composition of Willemite Zn,SiO..

5. Ten grams of silica are heated with fluor-spar and hydrogen sulphate, what volume of silicon fluoride at 13° C. is formed?

SiO, +2CaF, + 2H2SO, 2CaSO, + 2H2O + SiF.

2

=

6. What does a litre of hydrogen silicide (SiH) at 13° C. weigh?

7. What volume of chlorine at 26° C. is required to make 100 grams of silicon tetrachloride?