M.ixter — Acidic Oxides with Sodium Oxide. 



203 



1 2 



Silver 10000 grams 10-000 grams 



Sulphur 1-000 " 1-000 " 



Sodium peroxide -- 17- " 13- " 



Heat observed 5424 c 5596° 



Heat of oxidation of S and Fe 5320 c 5320° 



104° 276 c 



For 1 gram of silver 10 c 28 c 



The mixture in experiment 1 did not fuse but only sintered 

 together and the product contained no fused particles of silver. 

 The fusion of 2 was good and it left when digested with water 

 and acetic acid 6*8 grams of metallic silver, most of which was 

 in a fine powder. A few particles of fused silver were 

 present, showing that the temperature of the fusion was high. 

 The first result is low because the fusion was not good. 

 Sodium peroxide in water reduces silver oxide, hence it is im- 

 possible to determine how much of the silver in the mixture of 

 experiment 2 was attacked and it is best to consider that all 

 of it was. On this assumption the heat effect of 1 gram of 

 silver reacting with sodium peroxide is 28° and of 2 gram 

 atoms it is 6,000 c . 



Silver Oxide. 



The silver oxide used in the investigation was made by 

 adding potassium hydroxide to a solution of the nitrate. It 

 was thoroughly washed, dried in the air and then heated for 

 two days at 200° to 220° and finally the temperature was raised 

 and kept at 280° for several hours. The preparation contained 

 92-8 per cent of silver ; Ag 2 containing 93 - l per cent. It 

 was not quite free from carbonate, but gave off very little gas 

 when dissolved in nitric acid. It was preserved in a stoppered 

 tube. The experimental work was as follows : 



3 4 



Silver oxide 6*200 grams 4-897 grams 



Sulphur 1-500 * " 1-500 " 



Sodium peroxide 15- " 14- " 



Heat observed 8526° 8358 c 



Heat of S and Fe 7955° 7955° 



57l c 403 c 



For 1 gram of Ag 2 92° 81 c 



Some gas was given in experiment 3 in the combustion but 

 none in 4. Both fusions left a few minute particles of fused 

 silver when they were disintegrated by water and the fine 

 sediment floated off. The mean of the two results is 87°. 



