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equivalent rotational orientation; its number may be called the 
ByMMetry-numer Gp) er er, (GO) 
of the molecule. (For instance for J, 6 would be=2, for CH, 
(methane) 6 = 12). 
Finally we shall call /; the number of fully-excited degrees of 
freedom of the molecule; therefore 
Tee Oat as a 
according as the molecule in question contains one, two or more 
atoms. 
The numbers of the molecules of different kinds V,, V,,.... Ny, 
have to ey the Snol 
= MEX, =i, SNZ RE ao) 
Le. with varying degree a dissociation Hie numbers “Ni. Ns 
change, as also the total number of molecules 
j 
NEEM. © 
but not the numbers of the atoms. 
The total energy of-the gas-mixture is given by the equation 
HSK le Ne Koda volt Me Sheene ene 60) 
where K stands for the total kinetic energy of all the molecules. 
In the thermodynamic calculation of the dissociation-equilibrium 
(§ 6) we shall use “molar” instead of molecular quantities. Calling 
Avoerabo’s number 
NE eene nee mera CL 
we have the following relations for the number of gram-molecules 
ni, for the potential and kinetic energies pro gram-molecule (5%, Ci, T) 
and for the specific heat (Ci) respectively 
„et bei tn = Gane a (12) 
where 
(13) 
hence 
Tei Ee Nie te UN 
§ 4. The phase-space of the gas (y-space). The v-weight {+}. 
The most general “phase” of our system may be represented by 
the 6(X+ Y-+Z) cartesian co-ordinates and momenta of the 
