A sample consisting of $3\mathrm{.}00$ mol He is expanded isothermally and reversibly at $15\backslash$deg C from $30$ dm$3$ to $50$ dm$3.$ Calculate g$,$ w$,$ Change in Uand change in H$.$ Data: R $=8\mathrm{.}3145$ J K$-1$ mol$-1$