Use the van der Waals equation to plot the compressibility factor, Z , against pressure, P, for methane for temperatures T =180k ,189k ,190k , 200k , 250k . Note: plotting must be done using a computer program Hint: Calculate Z as a function of V and P as a function of V , and then plot Z vs. V . This approach results in a "parametric plot", which is inherently more complicated than plotting a single-variable function. Use whatever resource you like to learn about how to generate a parametric plot.
• What is the physical interpretation of compressibility factor, Z ? At what general pressure does the compressibility factor converge for all temperatures?
• What intermolecular forces result in a compressibility factor less than unity, Z <1? At what general pressure does this occur?
• What intermolecular forces result in a compressibility factor greater than unity, Z >1? What is the relationship between thermal energy, and other intermolecular forces, that causes this phenomenon? At what pressure does this occur?