A reaction is taking place in a rigid reactor under adiabatic process at initial temperature of $25\backslash$deg C$.$ Calculate the change in the specific internal energy of the system in kJ$/$mol

Report your answer up to $2$ decimal points. Do not truncate any intermediate steps, but only the final result.

A$->2$B $\backslash$Delta Hr$\backslash$deg $=-205\mathrm{.}6$ kJ at $25\backslash$deg C and $1$ atm