Now let's compare the pressure of ideal and real systems. Now, for the pressure of an ideal system, remember they're not feeling electrostatic forces and that means they hit the wall of the container and they're not attracted or repelled by other molecules. For real situations, for real gases, the pressure is less. Well, why is it less? Well, when the molecule in the real gas travels it's attracted by other molecules. And that means if it's attracted by other molecules if it's pulled by the other molecules it will hit the wall with less force and therefore, a smaller pressure will result.