Ideal gas equation is represented as PV=nRT. Gases present in the universe were found idealn the Boyle's temperature range only. The compressibility factor for an ideal gas, Z= (PV)/(nRT). The main cause to show deviations were due to wrong assumptions madebout forces of attractions (which becomes significant at high pressure).olume occupied by molecules V, in PV = nRT, is supposed to be volume ofas or, the volume of container in which gas is placed by assuming thataseous molecules do not have appreciable volume. Actual volume of theas is that volume in which each molecule of a gas can move freely. Ifolume occupied by gaseous molecule is not negligible, then the term Vhould be replaced by the ideal volume which is available for free motion ofach molecule of gas. Similarly for n moles of gas V_("actual") = V-nb The excluded volume can be calculated by considering bimolecular collisions. The excluded volume is the volume occupied by the sphere of 2r for each pair of molecule. Thus, excluded volume for one pair of molecules = 4/3 pi (2r)^3 = (4 xx 8 pi r^3)/3 The excluded volume for 1 molecule = 2/3 xx 8 pi r^3 = 4 xx (4/3 pi r^3) = 4V The excluded volume for N molecules = 4NV = b (where N is Avogadro's No.) The compressibility factor for N_2 at -50^@C and 800 atm pressure is 1.95. Number of moles of N_2 required to fill a balloon of 100 L capacity is :