9 2. Certain molecules adsorbed on a solid surface behave like a 2D gas whose molecular partition function can be shown to be as follows, 2m 9. =cAk T exp(Ex/k7), where cu is a constant ha A is surface area, and the attractive interaction energy per molecule with the surface is -E. (a) (15 pts) Develop an expression for the chemical potential of the adsorbed gas, Men (b) (25 pts) The chemical potential of the molecules in gas phase is ten = k,7 (In P - In 7" + a) where a is a constant and P, T are gas pressure and temperature, respectively. Considering M equilibrium M = Mud, show that the surface density of the adsorbed molecule, P can P be expressed as Pod=b- exp(es/k,T), where b is another constant TV2