Calculate the enthalpy change for transformation $W$. Show your working.
Use your answer to (a)(i) together with the other data to calculate the enthalpy change for transformation $Z$.
Use your answer to (a)(ii) to calculate the enthalpy change of hydration of $\text{Ca}^{2+}(g)$.
Write an expression, in terms of $W$, $X$, $Y$ and/or $Z$, to show how the enthalpy changes of two transformations can be used to calculate the lattice energy of $\text{CaCl}_2(s)$.
State whether the lattice energy of $\text{CaCl}_2(s)$ is more or less exothermic than the lattice energy of $\text{MgF}_2(s)$. Explain your reasoning.
The sulfates of the Group $2$ elements differ in solubility down Group $2$. Give the names of two solutions that could be mixed to form barium sulfate.
State and explain how the solubilities of the Group $2$ sulfates change down Group $2$.