Question

The parameter g varies with temperature for molecular
gases because of the varying contributions from molecular
vibrations. Determine g in the low-temperature and the hightemperature
limits for (a) CO2 (g) and (b) H2O (g).

Answer 1

Here g parameter may be gibbs free energy.

at low temperature the dipole dipole interaction increases and CO2 slowly convert to liquid sothat energy is released. and g value become negative i.e. exothermic process. at high temperature the molecules gain energy so they move away from each other for this energy required, hence it is endothermic process. so g value is positive

At low temperature there is formation of hydrogen bond between water molecules due to more electronegative difference between oxygen and hydrogen atoms.so here also energy is released hence it is exothermic process and g value become negative. at high teperature the molecule gains energy so they move with high kinetic energy and more reactive in this process energy absorbed hence it is endothermic process. and g value positive