(a(i))[1]
What does the enthalpy change of hydration mean?
(a(ii))[2]
Explain why the enthalpy changes of hydration of $\text{K}^+$ and $\text{Ca}^{2+}$ are different in magnitude.
(a(iii))[1]
Define the lattice energy.
(a(iv))[2]
For calcium fluoride, $\text{CaF}_2$, the lattice energy, $\Delta H_{latt}$, is $-2602\ \text{kJ mol}^{-1}$. Calculate the enthalpy change of solution, $\Delta H_{sol}$, in $\text{kJ mol}^{-1}$, for $\text{CaF}_2$.
(b)[2]
The formation of $\text{CaF}_2$ at $298\ \text{K}$ is shown. $\text{Ca}(s) + \text{F}_2(g) \rightarrow \text{CaF}_2(s)\quad \Delta H^{\circ} = -1214\ \text{kJ mol}^{-1},\ \Delta G^{\circ} = -1162\ \text{kJ mol}^{-1}$. Calculate the entropy change, $\Delta S^{\circ}$, in $\text{J K}^{-1}\ \text{mol}^{-1}$, for this reaction.