Final answer:
Bond energy, also known as bond dissociation energy, is the energy needed to break a covalent bond between two atoms. This energy is a measure of the bond's strength and stability, with higher energies indicating stronger bonds. This energy is required to overcome the attraction between bonded atoms, releasing the same amount when bonds are formed.
Step-by-step explanation:
The bond energy of covalent bonds is the energy required to break a bond between two atoms. The stronger the bond, the higher the bond energy, indicating that more energy is required to break the bond. For instance, the bond energy of a C-C bond is about 80 kcal/mol, while a double bond like C=C has a stronger bond with a bond energy of approximately 145 kcal/mol. Similarly, the bond energy for a diatomic hydrogen molecule (H-H) is 436 kJ per mole of H-H bonds broken. This energy is always positive because it is consumed to break bonds. It reflects the difference in energy between bonded atoms and separated atoms, meaning the same amount of energy is released when the bond initially forms.
Factors such as bond length and bond strength affect these energies, and molecules with high bond energies tend to be more stable and less reactive. Bond energies provide insights into the reactivity of molecules as well as the strength of their bonds. The bond dissociation energy is a specific measure for separating one mole of bonded atoms in the gaseous state.