# Why is the ideal gas law used?

Aug 24, 2016

To introduce you to the easiest case.

Ideal gases have several assumptions, some of them being:

• They do not react with each other.
• They collide 100% elastically, so their kinetic energy is retained/conserved.
• They take up the entire volume of their container, and do not "stick" to their container.
• They all have the same molar volume $\overline{V} = \frac{V}{n}$ at STP.

Real gases are significantly more complicated, and not all of them are ideal enough that they follow the ideal gas law. You would see that in their $\overline{V}$ value.

Later on, you may learn more equations of state that are more complicated than the ideal gas law, like the van der Waals, Redlich-Kwong, and Peng-Robinson equations of state, and those are more suited for real gases.