I'm reviewing a question on a previous test but am having trouble finding the solution for it. We were told to draw a PV diagram of a monoatomic ideal gas that undergoes an isothermal compression from Va to Vb and then is allowed to expand adiabatically and quasistatically back to Va again. I was able to comprehend this portion of the question fine but then got stuck on the next part that asked how this sketch would look if the molecule was diatomic. Aside from the difference in internal energy due to the degrees of freedom of a diatomic molecule I can't seem to find any other major implications of a monoatomic gas vs. a diatomic gas. Furthermore I can't seem to figure out how the internal energy of the system would tie into this diagram.