explain how the expression PV/RT can be used to show gases behave non ideally at high pressure
At high pressure the two basic assumptions behind the ideal gas law—namely, that gas molecules have negligible volume and that intermolecular interactions are negligible—are no longer valid.
For a mole of ideal gas (n = 1) the quantity PV/RT equals 1 at all pressures. When PV/RT is plotted as a function of P for 1 mol of several different gases. then we can see that at high pressures the deviation from ideal behavior (PV/RT = 1) is large and is different for each gas. This shows that real gases do not behave ideally at high pressure.
For a mole of ideal gas (n = 1) the quantity PV/RT equals 1 at all pressures. When PV/RT is plotted as a function of P for 1 mol of several different gases. then we can see that at high pressures the deviation from ideal behavior (PV/RT = 1) is large and is different for each gas. This shows that real gases do not behave ideally at high pressure.