For the reaction , kcal and cal/K at 300 K. What is the exact value of the Gibbs free energy change — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

First, find $\Delta H = \Delta U + \Delta n_g RT$. $\Delta n_g = 2 - 0 = 2$. $\Delta H = 2100 \text{ cal} + 2 \times 2 \times 300 = 3300 \text{ cal} = 3.3 \text{ kcal}$. Then, $\Delta G = \Delta H - T\Delta S = 3300 - 300(20) = 3300 - 6000 = -2700 \text{ cal} = -2.7 \text{ kcal}$.