The langmuir modelconsider a vapor of atom in equilibrium with atoms adsorbed to a surface. as atoms from a vapor phasebecome bound to a surface, they are restricted to discrete sites and are not free to move. each of the sitesoccupies an area a1 for a total of ns = a/a1 possible binding sites. only one atom can occupy each site. the binding energy for an atom on the surface is −ε0 . the mass of the atoms is m and both the surface andvapor are held at temperature τ.a) find the partition for the system of adsorbed atoms as a function of the number of adsorbed atoms z(nad ).b) calculate the chemical potential of the adsorbed atoms. c) use your expression for the chemical potential to find the equillibrium presure of the vapor as a functionof the number of adsorbed atoms nad /ns .