^' KT ^ 



E 



654 



logT^(2v,)logp-\ :E{v,C\), (3) 



in wliioli K represents tlie constant of dissociation in tlie relation 



/;-. , , 2.i' , -i — x 4f* 



^^— =: A' (for di-atomic eases, where k\ = — _ — , A- = ---— , -— 



k^-^v l+.T l+,r 1— a?' 



will be therefore = K, when .*; represents the so-called degree of 



dissociation and Ji\ etc. the so-called molecnlar concentrations), we 



cannot only theoretically f^et nearer to the constants C, etc. (the 



so-called chemical constants of (he components), and so also to 



^ {r^Ci)= C — this has been of late done by Lorentz, Planck, 



Sackur, Tetrode and others in virtue of considerations of probability 



in connection with the so-called theorem of heat of Nernst and 



Planck's theory of qnanta — but we can also calculate the heats 



of reaction Q^ for 7'^0. Up to now we had to be satisfied with 



determining ''^o- j"st as C = 2:{i\Ci), experimentally from a few 



values of .r, but now we should be able to calculate the value of 



/()ƒ/ A" at given temperature and pressure accurately for every gas 



reaction, as soon as oidy the values of the chemical constants and 



of V^ A and I ^a are accurately known for cveiy element separately. 



This must henceforth be the task of physicists: to get to know 



these values completely. They are essential for the knowledge of the 



behaviour of the chemical substances reacting on each other. When 



we are further acquainted witii all the values of b for the different 



elements, then Tk and />a- are known of every simple or compound 



substance, hence also their further thermical behaviour. 



among others my Lelirhuch der math. Chemie (Barth, 1901), p. 1 — 13,25 — 28, 

 and the '•'Sechs Vortrage" (Vieweg, 1906), p. 64 et seq. These latter appeared 

 originally in tlie Ghem. Weekbl. 1905]. 



Nernst has only said something about the constant "Li'j-^Ci) = C — which is in 

 connection with the constants of entropy — ill reference with his theorem. This 

 enabled him namely to bring the said quantities C^ (the "chemical constants") in 

 connection with the constants of the equations of the vapour pressure at very 

 low temperature. But all this has of course nothing to do with formula ("3) itself, 

 which is quite independent of the theorem of heat. The latter says only something 

 concerning the approach to of entropy, specific heat etc. in condensed systems, 

 in connection also with Planck's theory of quanta. 



When formula (3) {p constant) is differentiated with respect to T, we get: 



dT )i, RT^ '^ T 



And as l^^^^\=^^, Q^,^,„„,, = Qo + :Sh(ci+i2)]r, hence Q„=,,„,,= 

 = Qo+^(^i f'l) T, in perfect agreement with (c) of § 4. 



