Question

Values of \( \Delta G_f^0 \) (standard Gibbs free energy of formation) for molecules A, B, and C are \[ \Delta G_f^0(A) = -34 \, \text{kJ/mol}, \quad \Delta G_f^0(B) = 84 \, \text{kJ/mol}, \quad \Delta G_f^0(C) = -100 \, \text{kJ/mol}, \] respectively. The \( \Delta G^0 \) for the reaction \( A + B \rightarrow C \) would be ............ kJ/mol (round off to 1 decimal place)

Hint:

To calculate \( \Delta G^0 \) for a reaction, subtract the sum of the standard Gibbs free energies of the reactants from that of the products.

Answer 1

Correct Answer: -150.1

Step 1: Calculate \( \Delta G^0 \) for the reaction.
The change in Gibbs free energy for the reaction \( A + B \rightarrow C \) is calculated using:
\[ \Delta G^0_{\text{reaction}} = \Delta G_f^0(C) - \left( \Delta G_f^0(A) + \Delta G_f^0(B) \right) \] Substituting the values: \[ \Delta G^0_{\text{reaction}} = (-100) - (-34 + 84) = -100 - 50 = -50 \, \text{kJ/mol} \]
Step 2: Conclusion.
Thus, the correct answer is \( \boxed{-50} \, \text{kJ/mol} \).