For H2 at very low temperatures, only translational motion contributes to the heat capacity. At temperatures above eR = luBlk, the rotational contribution to the heat capacity becomes significant. At still higher temperatures, above ev = hulk, the vibrations contribute. But at this latter temperature, dissociation of the molecule into the atoms must be considered.

(a) Explain the origin of the expressions for eR and el" and calculate their values for hydrogen.

(b) Obtain an expression for the molar constant –pressure heat capacity of hydrogen at all temperatures taking into account the dissociation of hydrogen.

(c) Make a plot of the molar constant-pressure heat capacity as a function of temperature in the high-temperature region where dissociation of the molecule is significant.