Specific Heat of a Gas with Temperature. 3G1 



Take our case. The increase in translational energy for 

 a rise of 1° C. is 



= |nr. 



The increase in total energy for a rise of 1° 0. is 



~7; s "'l5E«) LtJ, *'* + J, *-''''J 



8 V J 



. 3 1 _ r . 2 \ A /l , _ x2 3 _^ 2 3 1 _ X 2V 

 #1 / V 2 4 8 a? A 



Therefore 



A(Tr) 3 



A (To) 3 + __«£ = |-^ + 1 ^ i2 , i terms) -0(> terms)]' 



and 7 = 1+ ^ . (4) 



3 + —^ [ (0 + 1) (pterins) - 0(a?terms) ] 



We are now in a position to calculate the values of <y for 

 hydrogen at low temperatures. Putting E = 625, we find 



_ 625 

 (0 + l)(tfi terms) =« •+! \ 7800(0 + 1) ~* 



+ 18'75(0 + l)* + 'O15(0 + l)f}, 



and a similar expression for 0(.r terms), the only change 

 being 6 for (0 + 1). After substituting these values in 

 equation (4), we obtain the following table : — 



Calculated values of 7 for hydrogen at low temperatures. 



Gabs 25 81 100 121 144 169 225 



Y 1-666 1645 1-608 1645 1-408 1-458 1408 



The change in 7 with the absolute temperature 6 is shown 

 Phil. Mag. Ser. G. Vol. 40. No. 237. Sept. 1920. 2 B 



