Why don't gases follow the ideal gas law at high temperatures?

In other situations such as high pressures and/or low temperatures, the ideal gas law might give answers that are different from what we observe experimentally. In these cases, you can use the van der Waals (or a similar) equation to take into account the fact that gases do not always behave as ideal gases. read more

The ideal gas law, PV = NkT, is an assertion that at thermal equilibrium, the mechanical potential energy (PV) is entirely equal to the random thermal energy (NkT). This assumes there is no other source of potential energy in the entire system -- that the molecules in the gas completely ignore each other. read more

At high temperatures and low pressures the ideal gas law is a very good model for gas behavior. Properties of the gaseous state predicted by the ideal gas law are within 5% for gases under ordinary conditions. read more