On what factors internal energy of ideal gas depends
Answers
the internal energy of an ideal gas, the internal energy is indeed dependent only on the absolute temperature for a given gas. But it also depends on the nature of the gas, that is, whether the gas molecules are monatomic, diatomic, etc. That is because the internal energy depends on the number of degrees of freedom associated with the molecules that make up the gas.
The internal energy of an ideal gas can be expressed as
where n is the number of moles of gas, Cv is the molar heat capacity (measured at constant volume), and T is the absolute temperature. And Cv is (3/2)R for monatomic gases (like He, Ne, Ar, etc.), (5/2)R for diatomic gasses (like H2, O2, N2, etc.) and can be larger for more complicated molecules which have more degrees of freedom associated with them, and where R is the universal gas constant (that is, the same R that is in pV=nRT).
That said, the more complicated the molecule, the less likely the conditions to satisfy the Ideal Gas Law can be satisfied (that is, the molecules are larger and more likely to interact with each other at lower densities than for monatomic gases).