IB Chemistry Topic R1.4 Entropy and Spontaneity…

For a reaction where $\Delta H > 0$ and $\Delta S < 0$ , what is the sign of $\Delta G$ at all temperatures?

Which of the following processes has a negative entropy change ( $\Delta S$ )?

Which of the following is always true at equilibrium?

Which of the following physical states has the highest entropy at a given temperature?

For a chemical reaction, the Gibbs free energy under non-standard conditions is given by:

$\Delta G=\Delta G^\circ+RT\ln Q$

Where:

$\Delta G^\circ = -10\ \mathrm{kJ\ mol^{-1}}$

$T = 298\ \mathrm{K}$

$Q = 0.10$

$R = 8.314\times 10^{-3}\ \mathrm{kJ\ mol^{-1}\ K^{-1}}$

(b) whether the reaction is spontaneous under these conditions.

Temperature dependent

$\text{H}_2\text{O}(l) \rightarrow \text{H}_2\text{O}(g)$

$\text{CO}_2(g) \rightarrow \text{CO}_2(s)$

$\text{NaCl}(s) \rightarrow \text{Na}^+(aq) + \text{Cl}^-(aq)$

$\text{NH}_4\text{NO}_3(s) \rightarrow \text{NH}_4^+(aq) + \text{NO}_3^-(aq)$

(a) the value of $\Delta G$ under these conditions.

IB Chemistry R1.4 Entropy and Spontaneity Questionbank