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

Consider the graph of $Gibbs$ free energy $G$ vs. Extent of reaction. The number of statement$(s)$ from the following which are true with respect to points $(a)$,$(b)$,and $(c)$ is $.................$
$A$. Reaction is spontaneous at $(a)$ and $(b)$
$B$. Reaction is at equilibrium at point $(b)$ and non-spontaneous at point $(c)$
$C$. Reaction is spontaneous at $(a)$ and non-spontaneous at $(c)$
$D$. Reaction is non-spontaneous at $(a)$ and $(b)$

Which of the following conditions are not suitable for a spontaneous reaction?

The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $T$ is given by $\Delta_{r}G^{o} = A - BT$,where $A$ and $B$ are non-$zero$ constants. Which of the following is $TRUE$ about this reaction?

For the reaction $C_{(graphite)} + CO_{2(g)} \rightarrow 2CO_{(g)}$,$\Delta H = 170 \ kJ$ and $\Delta S = 170 \ J/K$. At what temperature $(K)$ will the reaction become spontaneous?

The maximum work done in expanding $16 \ g$ of oxygen at $300 \ K$ from an initial volume of $5 \ dm^3$ to a final volume of $25 \ dm^3$ isothermally and reversibly is $(\log_{10} 5 = 0.699)$.