A SIMPLE EXPERIMENT IN CHEMICAL KINETICS. 45 



^■=-:^log 



â '^^ A-x 



0.00284 

 0.00316 

 0.00327 

 0.00324 

 0.00325 

 0.00324 

 0.00330 

 0.00330 

 0.00330 

 0.00330 

 0.00333 

 0.00333 

 0.00335 

 0.00340 

 0.00345 

 0.00350 



A, the initial pressure due to oxygen, was not directly measured 



but cnlculated out in the following' manner :- — 



A = (760 m.ni.— 17. in. in.) 0.209 = 155.3 m.ni. 



Where 760 m.m. : I^>nronietric height, 



17 ,, ,, : The vapor-tension of water, the teTn))erntnre of 



the surrounding water being 20.*'0 — 20.°1 during the 



experiment. 



20.9 7o : the percentage of oxygen in air. 



As the volume of air remained constant, the active mass of 



oxygen at time & is proportional to A—x, so that the equation 

 dx 



=^Ti{A — x) ought to be satisfied in this case. But ■ n did not 



-L 1 ^ 



diminish regularly as the time extended, and therefore —j- log —^ 



