The reaction $MgO_{(s)} + C_{(s)} \to Mg_{(s)} + CO_{(g)}$,for which $\Delta_r H^o = +491.1 \ kJ \ mol^{-1}$ and $\Delta_r S^o = 198.0 \ J \ K^{-1} \ mol^{-1}$,is not feasible at $298 \ K$. The temperature above which the reaction will be feasible is ..... $K$.

For a reaction at $25\,^oC$,the enthalpy change $(\Delta H)$ and entropy change $(\Delta S)$ are $-11.7 \times 10^3\, J \, mol^{-1}$ and $-105 \, J \, mol^{-1} K^{-1}$ respectively. The reaction is:

$A$ spontaneous process is impossible if ........

The maximum work (in $kJ \, mol^{-1}$) that can be derived from the complete combustion of $1 \, mole$ of $CO$ at $298 \, K$ and $1 \, atm$ is:
[Standard enthalpy of combustion of $CO = -283.0 \, kJ \, mol^{-1}$; standard molar entropies: $S_{O_2} = 205.1 \, J \, K^{-1} \, mol^{-1}$,$S_{CO} = 197.7 \, J \, K^{-1} \, mol^{-1}$,$S_{CO_2} = 213.7 \, J \, K^{-1} \, mol^{-1}$]

For the reaction $A \to B$,$\Delta H = 4 \, kcal \, mol^{-1}$ and $\Delta S = 10 \, cal \, K^{-1} \, mol^{-1}$. At what temperature $(K)$ will the reaction become spontaneous?

Under what conditions will a reaction become spontaneous at all temperatures?