Two elements, X and Y, combine to make a covalent molecule, as illustrated. This reaction gives out heat. $\text{X}_2(g) + \text{Y}_2(g) \rightarrow 2\text{XY}(g)$ The bond energies are listed in the table. What is the energy change for this reaction?
- A$+184\,\text{kJ mol}^{-1}$
- B$-184\,\text{kJ mol}^{-1}$
- C$+247\,\text{kJ mol}^{-1}$
- D$-247\,\text{kJ mol}^{-1}$