6 Bateman, Degrees of Freedom of a Molecule. 



2. Caiculatioi of the fiumber of degrees of freedom of 

 various molecules. 

 Hydrogen. If we assume the molecule to be represented by 

 the formula 



H— H. ;; = 4 + 4-3 = 5- 

 Chlorine. If the formula is assumed to be CI - CI, we get « = 5 

 which does not give a value of y agreeing with the 

 experimental one. If on the other hand we assume the 

 formula to be CI - - CI, we get « = 4 + 4-2 = 6. The 

 deviation of the value obtained by assuming « = 5, may, 

 however, be due to the fact that Chlorine is far from 

 being a perfect gas. 

 Oxygen. = 0. « = 5 + 5- 5 = 5. 

 Ozone. = = gives « = 5 + 7 + 5-5-5 = 7. 



O 



oOo 



rives « = 7 + 7 + 7-5 -5-5 = 6. 



p. gives « = 5 + 5 + 5-3-3-3 = 6. 

 0-^0 



It is possible that the first form is intermediate in the 

 formation of the second, so that in reality both types of 

 values occur. The recognised value of 7 is 129 which 

 corresponds to a value of n lying between 6 and 7. 



Carbon di-oxide O = C = O gives « = 7. 

 //Sa gives « = 6. 



just as in the case of ozone. The experimental value of 

 y is about I "3, which again corresponds to a value of n 

 lying between 6 and 7. In this case also, it is possible 

 that both kinds of molecules occur. 



Marsh Gas 



Fig. 6. « =7 + 16-12-5 = 6. 



Methyl Chloride 



Fig. 7. « = 7 + 12 + 4-9-2-2-2-1 = 7. 



