Zinc sulfide can be oxidized by oxygen gas according to the reaction 2 ZnS(s) +O₂ (g) ? 2 ZnO(s) + S(s).If $\Delta$H$\degree$=-289.0 kJ/mol and $\Delta$S$\degree$=-169.4 J/K.mol, what is $\Delta$G$\degree$ For this reaction at 25.00$\degree$C?

Question

Quizplus · Accepted Answer

The Gibbs free energy change ($\Delta G^\circ$) can be calculated using the equation $\Delta G^\circ = \Delta H^\circ - T\Delta S^\circ$, where $\Delta H^\circ$ is the change in enthalpy, $T$ is the temperature in Kelvin, and $\Delta S^\circ$ is the change in entropy. Given $\Delta H^\circ = -289.0$ kJ/mol and $\Delta S^\circ = -169.4$ J/K·mol, and the temperature $T = 25.00^\circ C = 298.15 K$, we convert $\Delta S^\circ$ to kJ by dividing by 1000, getting $-0.1694$ kJ/K·mol. Plugging these values into the equation gives $\Delta G^\circ = -289.0 kJ/mol - (298.15 K)(-0.1694 kJ/K·mol) = -289.0 kJ/mol + 50.5 kJ/mol = -238.5 kJ/mol$.

Zinc Sulfide Can Be Oxidized by Oxygen Gas According to the Reaction