Question

predict whether the following compounds will have an endothermic or ethermic enthaply change of solution based on the table below:
lithium chloride:(dissociation:853 - hydration:883- solution:??

Answer 1

To predict whether the dissolution of lithium chloride (LiCl) will be endothermic or exothermic, we can use the enthalpy changes associated with its dissociation and hydration.

Given:
- \( \text{Dissociation of LiCl} = 853 \, \text{kJ/mol} \) (energy required to separate the ions in the solid)
- \( \text{Hydration of Li}^+ \text{ and } \text{Cl}^- = 883 \, \text{kJ/mol} \) (energy released when the ions are surrounded by water molecules)

To find the overall enthalpy change of solution (ΔH_solution), we can use the formula:

\[
\Delta H_{\text{solution}} = \Delta H_{\text{dissociation}} - \Delta H_{\text{hydration}}
\]

Substituting in the values given:

\[
\Delta H_{\text{solution}} = 853 \, \text{kJ/mol} - 883 \, \text{kJ/mol} = -30 \, \text{kJ/mol}
\]

Since ΔH_solution is negative (-30 kJ/mol), the dissolution of lithium chloride is exothermic.

In conclusion, the enthalpy change of solution for lithium chloride will be exothermic.