Describe an ideal gas and compare it to a real gas. Why do many real gases behave as ideal gases?
The question is backwards, really. The concept of “ideal gas” was formed after observing real gases. People were trying to explain the behavior of real gases. Ideal gases behave much like real gases because otherwise the theory would be no use . In an ideal gas, the molecules have no volume, undergo no chemical interactions, and all their collisions are elastic. In real gases, the size of the molecules is close enough to zero to make little difference except under extremely high pressure (or as they liquefy). Most of the gases you’re concerned with aren’t undergoing any chemical interactions, and the molecular collisions are mostly elastic except at extreme temperatures. The theory says those things don’t matter because they seldom do.
