Write an equation, including state symbols, to represent the process that occurs when the enthalpy of solution of calcium bromide, CaBr2\text{CaBr}_2CaBr2, is measured.
Table 1 shows some thermodynamic data.
Table 1
| Process / Quantity | Enthalpy change / kJ mol−1\text{kJ mol}^{-1}kJ mol−1 |
|---|---|
| Enthalpy of lattice dissociation of CaBr2\text{CaBr}_2CaBr2 | +2176+2176+2176 |
| Enthalpy of hydration of Ca2+(g)\text{Ca}^{2+}(g)Ca2+(g) | −1650-1650−1650 |
| Enthalpy of hydration of Br−(g)\text{Br}^-(g)Br−(g) | −335-335−335 |
Use the data in Table 1 to calculate the value for the enthalpy of solution of calcium bromide.
The enthalpy of hydration of Mg2+(g)\text{Mg}^{2+}(g)Mg2+(g) is −1920 kJ mol−1-1920\text{ kJ mol}^{-1}−1920 kJ mol−1.
Suggest why the enthalpy of hydration for Mg2+(g)\text{Mg}^{2+}(g)Mg2+(g) is more exothermic than that of Ca2+(g)\text{Ca}^{2+}(g)Ca2+(g).
27 exam-style questions on AQA A Level Chemistry Thermodynamics (A-level only), covering Born–Haber cycles (A-level only) and Gibbs free-energy change, $\Delta G$ , and entropy change, $\Delta S$ (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.