For a given chemical reaction $\mathrm{A} \rightarrow \mathrm{B}$ at 300 K the free energy change is $-49.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and the enthalpy of reaction is $51.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The entropy change of the reaction is $\_\_\_\_$ $\mathrm{J} \mathrm{K}^{-1} \mathrm{~mol}^{-1}$.