Question

The standard Gibbs free energy change $(\Delta G^\circ)$ at 25$^{\circ}$C for the dissociation of $N_2O_4(g)$ to $NO_2(g)$ is (given, equilibrium constant = $0.15, R = 8.314 \, J/K/mol)$

• A. $1.1 \,kJ$
• B. $4.7 \,kJ$
• C. $8.1\, kJ$
• D. $38.2\, kJ$

Answer 1

Answer: (B)

$4.7 \,kJ$

Answer 2

$\Delta G^{\circ}=-2.303 \,R T \log K$ $=-2.303 \times 8.314 \times 298 \times \log 0.15$ $=-2.303 \times 8.314 \times 298 \times(-0.82)$ $=4678.7 \,J =4.67\, kJ$