on the Rate of Chemical Change. 



327 



From the foregoing table it will be seen that the ratio — — 



On+l 



has, as nearly as possible, a constant value, the mean from all 

 the experiments being equal to T093. It would seem there- 

 fore that / (6) may be written in an exponential form and 

 equation (1) becomes 



&_, 



dt 



• a «y. 



In this particular reaction, taking the mean value for a as 

 given above, and the rate of oxidation at 10° 0. as unity, the 

 rate p at temperature 6° C. is represented by the equation 



p=(l-093)*- 10 °. 



In the following Table the rates at the different tempera- 

 tures, as determined experimentally by the ratio — ^, and as 



be 

 calculated from the above equation, are given ; and it will be 

 seen that there is a close agreement between the two series of 

 numbers. 



Table II. 



Temp. 0°. 



Rate of 



oxidation. 



Calculated 



rate of 

 oxidation. 



Temp. C°. 



Rate of 



oxidation. 



Calculated 



rate of 

 oxidation. 



10 



1-00 





20 



251 



243 



11 



MO 



1-09 



21 



2-73 



2-66 



12 



1-21 



119 



22 



2-96 



291 



13 



1-33 



1-31 



23 



332 



3-18 



14 



1-46 



1-43 



24 



359 



3-47 



15 



1-62 



1-56 



25 



383 



3-80 



16 



1-73 



1-70 



28 



5-08 



4-96 



17 



1-92 



1-86 



30 



604 



5-92 



18 



2-11 



2-04 



32 



7-15 



7-07 



19 



2-29 



223 









In a previous paper, already referred to, it was suspected 

 that p oc 2 ; but as the experiments were too few in number 

 and between too narrow limits of temperature, the actual re- 

 sults were not given. It may be of interest, therefore, to see 

 how far the present series of experiments bear this supposition 

 out. 



Representing the relation between rate and temperature by 

 the equation p = *;(0 + ?z) 2 , taking p 10 = /e(10 + n) 2 = l, the 

 following are the values obtained for n : — 



