Positive and positive

Positive and negative

Negative and positive

Negative and negative

$\Delta G$ is equal to $\Delta G^{\circ}$ when the system is at the standard state.

$\Delta G^{\circ}$ is zero when the system is at equilibrium.

$\Delta G$ measures activation energy of a reaction.

When $\Delta G$ is positive, the reaction should proceed forward to form more product.

$\mathrm{NaCl}(\mathrm{s}) \longrightarrow \mathrm{Na}(\mathrm{g})+\mathrm{Cl}(\mathrm{g})$

$\mathrm{NaCl}(\mathrm{s}) \longrightarrow \mathrm{Na}^{+}(\mathrm{g})+\mathrm{Cl}^{-}(\mathrm{g})$

$\mathrm{Na}(g)+\mathrm{Cl}(g) \longrightarrow \mathrm{NaCl}(s)$

$\mathrm{Na}^{+}(g)+\mathrm{Cl}^{-}(g) \longrightarrow \mathrm{NaCl}(\mathrm{s})$

$\mathrm{H}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{H}(\mathrm{g})$

Liquid water crystallises to ice

Temperature of ice is raised from 10 K to 115 K

$2 \mathrm{NaHCO}_3$ (s) $\longrightarrow \mathrm{Na}_2 \mathrm{CO}_3$ (s) $+\mathrm{CO}_2$ (g) $+\mathrm{H}_2 \mathrm{O}$ (s)