For a reaction,$\Delta H = -40 \, kJ$ and $\Delta S = -50 \, J/K$. At what temperature range will it change from spontaneous to non-spontaneous?

Calculate the work done in Joules $(J)$ when $50 \ g$ of iron is dissolved in $HCl$ in an open beaker at $25 \ ^oC$. The atmospheric pressure is $1 \ atm$.

The essential condition for the feasibility of a reaction is that

The standard entropy change for the reaction $4 Fe ( s ) + 3 O_{2} ( g ) \rightarrow 2 Fe_{2} O_{3} ( s )$ is $-550 \ J K^{-1}$ at $298 \ K$. Given: The standard enthalpy change for the reaction is $-165 \ kJ \ mol^{-1}$. The temperature in $K$ at which the reaction attains equilibrium is ... . (Nearest Integer)

For a reaction $A + B \rightarrow$ products,$\Delta H = -84.2 \ kJ$ and $\Delta S = -200 \ J \ K^{-1}$. Calculate the highest value of temperature (in $K$) so that the reaction will proceed in the forward direction.

Gibbs free energy $G$,enthalpy $H$ and entropy $S$ are interrelated as in