What is the work done when $1 \, \text{mole}$ of a gas expands isothermally and reversibly from $25 \, \text{L}$ to $250 \, \text{L}$ at a temperature of $300 \, \text{K}$? (in $J$)

$\Delta G$ is net energy available to do useful work and is thus a measure of "free energy". Show mathematically that $\Delta G$ is a measure of free energy. Find the unit of $\Delta G$. If a reaction has positive enthalpy change and positive entropy change,under what condition will the reaction be spontaneous?

Under what conditions does a reaction always occur spontaneously?

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:

In which of the following conditions will a reaction always be spontaneous at all temperatures?

$A$ process has $\Delta H = 200 \ J \ mol^{-1}$ and $\Delta S = 40 \ J \ K^{-1} \ mol^{-1}$. Choose the minimum temperature above which the process will be spontaneous.