208 

 tlie riieasnrea temp. coeu. is not = -— , but = —j X • 



' k] I^T CcatT 



Accordingly the real temp. coef. would be smaller than the 



measured one. 



Let lis suppose the bound catalyst to be totally inactive, and the 



true temp. coef. to iiave remained of the same value as was 



found in the non-catalysed reaction. The measured temp. coef. 



c' c' 



=:8 = 1,8X— ^, from which — ^:=:1,67, in other words one is 



C cat ^ cat 



confronted by the question whether it is possible that in the neigh- 

 bourhood of room temperature the concentration of the components 

 increases by 67 7o P^i' 10° increase of temperature. 



Let us take 300° and 310° absolute for the two temperatures, 

 0,1111 as constant of equilibrium at 300° (hence 90 V, bound cat, 

 10 7o ^I'ee cat), and let us put the heat of dissociation ^= 5000 cal, 

 a heat which may be called normal. 



10 X CA _ ^ Xc'a 



^•"^ 90 '''—100-.V 



in which ca=c'a «nay be |)ut: 



^310 ^ 



It follows from the reaction-isochore that 



= 0,1176 



c cat 



Hence even in the most unfavourable case conceivable that the 

 bound catalyst would be totally inactive, the increasing dissociation 

 per 10° increase of temperature is only able to account for a small 

 part of the increase of the temp. coef. of the catalysed reaction 

 above that of the non-catalysed reaction. 



ScHEFFE'.R pointed out that in many cases the K may be put 

 practically constant over a limited range of temperature, and that 

 in this case B is also pretty well constant. If the region from 

 20° — 50° lies within this limited range, (he values of Ink drawn 



