TEMPERATURE OF THE RATE OF A CHEMICAL CHANGE. 
201 
t. 
rn. 
ra. 
80 
37 • 6 
110 
34-7 
90 
36 • .5 
120 
33-8 
100 
35 • 6 
130 
33-0 
XIII. (6) ‘ Influence of the Temperature on the Rate of Hydrolysis of Ethyl 
Acetate by Caustic Soda,’ Warder. 
The author’s formula is 
log^ h = 5579T“^ ; 
hence 
711 = (/j“VZ/i-)/(T“VZT) = 5579T“\ 
t 
m. 
t. 
m. 
3-6 
20-2 1 
27-0 
18-6 
5-5 
20-0 
28-4 
18-5 
7-2 
19-9 
30-4 
18-4 
11-0 
19-6 
32-9 
18-2 
12-7 
19-5 
34-0 
18-2 
19-3 
19-1 
35-0 
18-1 
20-9 
19-0 
37-7 
17-9 
23-6 
18-S 
In X. and XI. in increases with the temperature: in X. from 27"2 at 15° C. to 
35‘4 at 101° C.; in XI. from 31‘9 at 70° C. to 37'5 at 130° C. In XII. and XIII. 
rn decreases with the temperature: in XII. Rom 37‘6 at 80° C. to 33 at 130° C. ; in 
XIII. from 20'2 at 3°‘6 C. to 17‘9 at 37°‘7 C. It is remarkable that in the experiments 
by Schwab, XI., XII., the sum of the values of in at each temperature from 80° C. to 
130° C. is very nearly constant, having a mean value 70'3. The two experiments 
taken together give a mean value of m = 35T7. 
The value of in is the same at the temperature given by ■093T = 13280T“h i.e., at 
T = 377'9 or t = 104’9. At this temperature in — 35T4. It would appear from this 
that if the conditions for a stable communication of heat energy to chemical energy 
had been secured in each set of experiments the constant value of in would have 
been 35T. 
The relation of m to temperature is in X. and XI. in = cT, and in XII. and XIII. 
in — 6T“L These relations are probably merely empirical, and are used in this paper 
to obtain approximate values of in at each temperature. Van ’t Hoff’s formula 
for in is 
in = {k-\lk)l{T-^dT) = 6T-^ + a + cT, 
which he deduces from the principles of thermodynamics. In the experiments 
discussed by him, a, h, c are made equal to zero in succession, but no reason is given 
VOL. CCXII.—A. 2 D 
