Final answer:
To calculate the energy of an H-Br bond, we need to sum the energies required to break the H-H and Br-Br bonds and consider the energy released upon forming the H-Br bonds. The energy of an H-Br bond, considering the provided data, should be -261 kJ/mol. However, this is not an option provided, indicating there might be a typo or the need for more accurate data.
Step-by-step explanation:
To calculate the energy of an H-Br bond, we need to consider the energy involved in breaking the bonds in the reactants and forming the bonds in the products. The given enthalpy changes for the reactions are as follows:
- H₂(g) + Br₂(g) → 2HBr(g): ΔH° = -103 kJ
- H₂(g) → 2H(g): ΔH° = 432 kJ
- Br₂(g) → 2Br(g): ΔH° = 193 kJ
Using this data, we can apply Hess's law to find the H-Br bond energy. Considering that breaking a bond requires energy and forming a bond releases energy, the energy required to break one mole of H₂ and Br₂ is:
- H-H bond: 432 kJ/mol (1 mole)
- Br-Br bond: 193 kJ/mol (1 mole)
The energy released upon forming two moles of H-Br bonds is given by the enthalpy change of the reaction with H₂ and Br₂, which is -103 kJ. Our calculation is as follows:
(432 kJ) + (193 kJ) = (2 x Energy of H-Br bond) + 103 kJ
Solving for the energy of one H-Br bond, we get:
625 kJ = 2 x Energy of H-Br bond + 103 kJ
2 x Energy of H-Br bond = 625 kJ - 103 kJ
2 x Energy of H-Br bond = 522 kJ
Energy of H-Br bond = 261 kJ/mol
Therefore, the energy of an H-Br bond is -261 kJ/mol (since bond formation releases energy). This option is not listed, so there may be a typo or error in the presented options or the student may need to check the values against a more current or exact source.