The results of either of the two preceding problems can

Chapter 3, Problem 26P

(choose chapter or problem)

Problem 26P

The results of either of the two preceding problems can also be applied to the vibrational motions of gas molecules. Looking only at the vibrational contribution to the heat capacity graph for H2 shown in below Figure, estimate the value of ϵ for the vibrational motion of an H2 molecule.

Figure: Heat capacity at constant volume of one mole of hydrogen (H2) gas.Note that the temperature scale is logarithmic. Below about 100 K only the threetranslational degrees of freedom are active. Around room temperature the tworotational degrees of freedom are active as well. Above 1000 K the two vibrationaldegrees of freedom also become active. At atmospheric pressure, hydrogen liquefiesat 20 K and begins to dissociate at about 2000 K. Data from Woolley et al. (1948).