The enthalpy change of formation of $\text{Mn(NO}_3)_2(s)$ is $-696\,\text{kJ mol}^{-1}$. The enthalpy change of formation of $\text{MnO}_2(s)$ is $-520\,\text{kJ mol}^{-1}$. The enthalpy change of formation of $\text{NO}_2(g)$ is $+33\,\text{kJ mol}^{-1}$. When heated, $\text{Mn(NO}_3)_2$ breaks down to form $\text{MnO}_2$ and $\text{NO}_2$. $\text{Mn(NO}_3)_2(s) \rightarrow \text{MnO}_2(s) + 2\text{NO}_2(g)$. What is the standard enthalpy change for this reaction?
- A$-242\,\text{kJ mol}^{-1}$
- B$-209\,\text{kJ mol}^{-1}$
- C$+209\,\text{kJ mol}^{-1}$
- D$+242\,\text{kJ mol}^{-1}$