What Is the Standard Enthalpy of Formation of
CaCO₃(s)

What is the standard enthalpy of formation of
CaCO₃(s) + CaO(s) + CO₂(g) ? CaCO₃(s) ; ?H° = -179.4 kJ/mol-rxn
$$\begin{array} { l l } \text { Substance } & \Delta _ { f } H ^ { \circ } ( \mathrm { kJ } / \text { mol-rxn } ) \\\mathrm { CaO } ( s ) & - 634.9 \\\mathrm { CO } _ { 2 } ( g ) & - 393.5\end{array}$$

A) 62.0 kJ/mol-rxn
B) -420.8 kJ/mol-rxn
C) -849.0 kJ/mol-rxn
D) -1207.8 kJ/mol-rxn
E) 849.0 kJ/mol-rxn