•Real gases have real volume.–Gas particles are notpoints of mass, but have volumes determined by the sizes of their atoms and the bonds between them.•Real gases do experience attractive and repulsive forces between their particles.•Real gases deviate most from ideal behavior at low temperatureand high pressure.
5-69GasMolar Volume(L/mol)Boiling Point(oC) HeH2NeIdeal gasArN2O2COCl2NH322.43522.43222.42222.41422.39722.39622.39022.38822.18422.079-268.9-252.8-246.1‒-185.9-195.8-183.0-191.5-34.0-33.4Table 5.3Molar Volume of Some Common Gases at STP (0°C and 1 atm)
5-70Figure 5.23Deviations from ideal behavior with increasing external pressure
5-71Figure 5.24The effect of interparticle attractions on measured gas pressure.
5-72Figure 5.25The effect of particle volume on measured gas volume.
5-73The van der Waals equation•The van der Waals equation adjusts the ideal gas law to take into account–the real volume of the gas particles and–the effect of interparticle attractions.(Pn2aV2)(Vnb)nRTVan der Waalsequation for nmoles of a real gasThe constant arelates to factors that influence the attraction between particles.The constant brelates to particle volume.
5-740.0340.2111.352.324.190.2441.391.366.492.251.453.594.175.46HeNeArKrXeH2N2O2Cl2CH4COCO2NH3H2O 0.02370.01710.03220.03980.05110.02660.03910.03180.05620.04280.03950.04270.03710.0305Gasaatm∙L2mol2bLmolTable 5.4Van der Waals Constants for Some Common Gases