unspecified process, the final state is $1\mathrm{.}5$ bar and $0\mathrm{.}027$ m$\text{'}.$ Assume air to be in its ideal$-$gas state and assume constant heat capacities C$/\backslash$deg $-20\mathrm{.}785$ and C$/\backslash$deg $-29\mathrm{.}100$ J$.$ mol!.K$!.$Calculate the change in the molar internal energy of the ideal gas system. Support your results by developing an expression.