For a process occurring at constant temperature and pressure,which of the following is true at equilibrium?

$\Delta G$ 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?

For an endothermic reaction at constant temperature $T$ and pressure $P$,if the process is spontaneous,which of the following is true?

$A$ $4.50 \ g$ sample of methane occupies $12.7 \ L$ at $310 \ K$. Calculate the work done in $J$ when the gas undergoes isothermal expansion against a constant external pressure of $200 \ torr$ until the volume increases by $3.3 \ L$. (in $.99$)

$A$ 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.

Which of the following set of thermodynamic conditions is true for the reaction to be spontaneous at high temperature?