Questions: Entropy and Free Energy Calculating standard reaction free energy from standard free energies of ... Using the thermodynamic information in the ALEKS Data tab, calculate the standard reaction free energy of the following chemical reaction: 4 H2O2(l) + PbS(s) → PbSO4(s) + 4 H2O(l) Round your answer to zero decimal places.

Solution Steps

To calculate the standard reaction free energy (\(\Delta G^\circ_{\text{rxn}}\)), we need the standard free energies of formation (\(\Delta G^\circ_f\)) for each compound involved in the reaction. These values are typically found in thermodynamic tables.

The given reaction is:

\[ 4 \mathrm{H}_{2} \mathrm{O}_{2}(l) + \mathrm{PbS}(s) \rightarrow \mathrm{PbSO}_{4}(s) + 4 \mathrm{H}_{2} \mathrm{O}(l) \]

The compounds involved are:

• \(\mathrm{H}_{2} \mathrm{O}_{2}(l)\)
• \(\mathrm{PbS}(s)\)
• \(\mathrm{PbSO}_{4}(s)\)
• \(\mathrm{H}_{2} \mathrm{O}(l)\)

The standard reaction free energy is calculated using the formula:

\[ \Delta G^\circ_{\text{rxn}} = \sum \Delta G^\circ_f (\text{products}) - \sum \Delta G^\circ_f (\text{reactants}) \]

Assuming the standard free energies of formation are:

• \(\Delta G^\circ_f (\mathrm{H}_{2} \mathrm{O}_{2}(l)) = a \, \text{kJ/mol}\)
• \(\Delta G^\circ_f (\mathrm{PbS}(s)) = b \, \text{kJ/mol}\)
• \(\Delta G^\circ_f (\mathrm{PbSO}_{4}(s)) = c \, \text{kJ/mol}\)
• \(\Delta G^\circ_f (\mathrm{H}_{2} \mathrm{O}(l)) = d \, \text{kJ/mol}\)

The calculation becomes:

\[ \Delta G^\circ_{\text{rxn}} = [c + 4d] - [4a + b] \]

Substitute the actual values from the data tab into the equation and perform the calculation. Round the final result to zero decimal places.

Final Answer