For the reaction:
$3Fe_{(s)} + 2O_2{(g)} \rightarrow Fe_3O_4{(s)}$
$\Delta H = -1650\,\text{kJ mol}^{-1}$, $\Delta S = -600\,\text{J K}^{-1} \text{mol}^{-1}$ at $300\,\text{K}$. What is the value of free energy change for the reaction at $300\,\text{K}$?
Two similar metallic rods of the same length \( l \) and area of cross section \( A \) are joined and maintained at temperatures \( T_1 \) and \( T_2 \) (\( T_1>T_2 \)) at one of their ends as shown in the figure. If their thermal conductivities are \( K \) and \( \frac{K}{2} \) respectively. The temperature at the joining point in the steady state is: