Calculate ${\mathrm{\Delta }}_r{G}^{\circ }$for $\left({\mathrm{NH}}_4\mathrm{Cl},s\right)$ at $310\mathrm{K}$

Given: ${\mathrm{\Delta }}_r{H}^{\circ }\left({\mathrm{NH}}_4\mathrm{Cl},s\right)=-314.5\mathrm{kJ}/\mathrm{mol};{\mathrm{\Delta }}_r{C}_p=0$

$\begin{array}{l}{S}_{{\mathrm{N}}_2\left(g\right)}^{\circ }=192{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1};S_{{\mathrm{H}}_2\left(g\right)}^{\circ }=130.5{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1};\\ S_{{\mathrm{Cl}}_2\left(g\right)}^{\circ }=233{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1};S_{{\mathrm{NH}}_4\mathrm{Cl}\left(s\right)}^{\circ }=99.5{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}\end{array}$

All given data at 300 K.