O2 has a bond energy of approximately 498 kJ.
Ca and O have a bond energy of approximately 315 kJ.
1. How much energy is absorbed when all reactant bonds are broken?
2. How much energy is released when the products are formed?
Note: Two CaO bonds are formed so you must double the bond energy.
3. Is more energy absorbed or released?
4. Is this overall endothermic or exothermic?