Final answer:
The energy required to break one mole of hydrogen bonds (H-H) in the gas phase is 436 kJ/mol. This value reflects the significant amount of energy needed for bond dissociation in molecular hydrogen, demonstrating the strong nature of the chemical bond.
Step-by-step explanation:
The amount of energy required to break a hydrogen bond in a molecule in the gas phase, also known as the bond energy, is a key concept in thermochemistry. In the case of molecular hydrogen (H₂), breaking one mole of H-H bonds requires a substantial amount of energy. Specifically, it takes 436 kJ/mol to break the bonds in one mole of hydrogen molecules and allow the atoms to separate into individual hydrogen atoms. This process is endothermic because energy must be added to break the bonds.
When considering bond energies on a per-mole basis, which is common in chemistry, we understand the significant energy involved in these chemical processes. For instance, although it requires only 7.24 × 10⁻¹¹ J to break a single H-H bond, the energy scales up to 436 kJ when dealing with one mole of H-H bonds.