For a certain reaction, $\Delta H = -50 \text{ kJ}$ and $\Delta S = -100 \text{ J/K}$. Find the temperature range at which the reaction is spontaneous.

Calculate the work done during the reversible isothermal expansion of $2 \ mol$ of an ideal gas at $298 \ K$ from $10 \ L$ to $20 \ L$ in $J$. (in $.9$)

Calculate $\Delta H_f^o$ for $UBr_4$ from the $\Delta G^o$ of reaction and the $S^o$ values: $U_{(s)} + 2Br_2(\ell) \to UBr_{4(s)}$; $\Delta G^o = -788.6 \ kJ$; $S^o \ (J/K \cdot mol): U_{(s)} = 50.3, Br_2(\ell) = 152.3, UBr_{4(s)} = 242.6$.

The criterion for a spontaneous process is

Calculate the work done in the following reaction at $27^{\circ} C$.
$4 SO_{2(g)} + 2 O_{2(g)} \rightarrow 4 SO_{3(g)}$
$(R = 8.314 \ J \ K^{-1} \ mol^{-1})$ (in $J$)

For a certain reaction,the enthalpy change and entropy change are $40.63 \ kJ \ mol^{-1}$ and $100 \ J \ K^{-1} \ mol^{-1}$ respectively. What will be the value of $\Delta G$ at $27 \ ^oC$?