A Simple Experiment in Chemical Kinetics. 



by 

 K. Ikeda, Rièakushi. 



The usual lecture experiment of absorbing oxygen from air by 

 a piece of phosphorus presents a very simple case of ciiemical kinetics. 

 For, if the lump of phosphorus employed be not too small, the nctive 

 surface remains practically constant, and the chemical action must h^ 

 proportional to the density of the oxygen left. The course of the 

 chemical change can be followed by observing the diminution of 

 pressure or of volume. The chief disturbing effect is the elevation 

 of temperature consequent on the oxidation, but this can be prevented 

 to a great extent by keeping the phosphorus cool. 



To this end a sufficient quantity of pure clear phosphorus was 

 melted between two test-tubes ; the inner tube was 

 next filled with cold water when phosphorus solidified 

 and could be easily drawn out of the external tube. 

 In this manner a uniform cylinder of phosphorus was 

 formed around the lower part of the smaller test-tul)e. 

 Any irregularities in surface of the phosphorus were 

 removed with a sharp knife, and the whole carefully 

 smoothed. Tlie phosphorus cylinder thus prepared 

 was about 30 m.m. long, a little less than 1 m.m. 

 thick, and 12 m.m. in external diameter, so that the 

 total surface was very nearly 11 square cm. To 

 keep this cylinder cool, the test-tube was fitted with Fig. 1. 



