Is this question formulated correctly? If not, please fix it and return the output as a JSON of the form: {'question': 'question text'}. Here is the question: Calculate ΔH° for the reaction H2(g) + Br2(g) → 2 HBr(g) using bond energy values. The ΔH°f of HBr(g) is not equal to one-half of the value calculated. Account for the difference.

Verified step by step guidance

1. Step 1: Understand the problem. We need to calculate the enthalpy change (ΔH°) for the reaction using bond energies and then compare it to the standard enthalpy of formation (ΔH°f) of HBr(g).
2. Step 2: Write the balanced chemical equation: H2(g) + Br2(g) → 2 HBr(g).
3. Step 3: Identify the bonds broken and formed. Breaking bonds requires energy, while forming bonds releases energy. In this reaction, we break one H-H bond and one Br-Br bond, and form two H-Br bonds.
4. Step 4: Use bond energy values to calculate the total energy change. The formula is: ΔH° = Σ(Bond energies of bonds broken) - Σ(Bond energies of bonds formed).
5. Step 5: Compare the calculated ΔH° with the given ΔH°f of HBr(g). If they differ, consider factors such as experimental conditions or the precision of bond energy values that might account for the discrepancy.