Q.What are ideal gases? In what way do real gases differ from ideal gases.

Step 1. An ideal gas is defined as one whose molecules occupy negligible volume compared to the container, and which experience no intermolecular attractive forces -- so that it obeys $PV=nRT$ exactly, at every pressure and temperature.

Step 2. No real gas actually satisfies both assumptions perfectly. Real gas molecules do occupy a small but genuinely nonzero volume, and they do attract one another -- proven by the simple fact that every real gas can be liquefied under suitable conditions, which would be impossible if there were truly no attraction between molecules. …

Define an ideal gas by its two kinetic-theory assumptions, then explain concretely why an …

• Giving only the definition of an ideal gas without explaining the actual physical reason real gases differ (finite volume and real attraction). …