88 



KINETICS OF CHEMILUMINESCENCE 



A flask of known volume was used to add oxygen to the system. 

 Before adding oxygen the entire system was evacuated to as low a 

 pressure as possible. Stopcock 4, connecting the reaction vessel with 

 the vacuum pump, was then shut off, and the system allowed to come 

 to equilibrium with respect to water vapor. Stopcock 5 was then 

 closed, and oxygen was added to the flask 6 and the pressure was 

 noted. By noting the pressure change when 5 was opened, a check 

 could be obtained on the volume occupied by the oxygen in the 

 manometer and reaction vessel. A small correction was found neces- 



Magnetic 



stirrer 



3 



Vi/ 



To vacuum 



Fig. 7. 



sary to compensate for the different volume displaced by the mercury 

 in the manometer as the level changed. The temperature of the reac- 

 tion solution was measured by a 0.1-degree thermometer. 



Procedure 



The distilled water used was boiled to remove as much dissolved 

 oxygen as possible. Sodium hydroxide and luminol were added, and 

 the solution was boiled under reduced pressure to remove as much of 

 the residual oxygen as possible. The solution was concentrated to the 

 correct volume by boiling off the excess water, and the temperature 

 was adjusted. Pure oxygen was added, and the pressure was noted. 

 The solution was stirred by means of the magnetic stirrer, and the rate 



