Final answer:
The heat of formation for PbS is -663.9 kJ/mol.
Step-by-step explanation:
To determine the heat of formation for PbS, we can use Hess's law and the given equation. First, we need to identify the elements involved in the reaction and their standard enthalpies of formation. Using the table provided, we can find the AHf for each substance: O2 (g) = 0 kJ/mol, SO2 (g) = -296.9 kJ/mol, PbO (s) = -217.3 kJ/mol.
Next, we can calculate the AHf for PbS using the equation and the AHf values:
- 2 PbS (s) + 3 O2 (g) → 2 SO2 (g) + 2 PbO (s)
- AH° = -828.4 kJ/mol
Using the equation and the given values, we can set up the equation:
2(-217.3 kJ/mol) + 3(0 kJ/mol) = 2(-296.9 kJ/mol) + 2 PbS (s)
Simplifying the equation, we find that the AHf for PbS is -663.9 kJ/mol.