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?

$\Delta G$ 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?

Describe Gibbs energy and spontaneity.

$A$ 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.

If the enthalpy and entropy change for a reaction at $298 \ K$ are $-145 \ kJ \ mol^{-1}$ and $-650 \ J \ K^{-1} \ mol^{-1}$ respectively,which one of the following statements is correct?

For a certain reaction, $\Delta H = -50 \text{ kJ}$ and $\Delta S = -100 \text{ J/K}$. Find the temperature range at which the reaction is spontaneous.