The total heat of hydration of 1 mol of gas phase Li⁺ ions and Cl^- ions is -865 kJ. The lattice energy of LiCl(s)is 828 kJ/mol. Calculate the heat of solution of LiCl.

Question

Quizplus · Accepted Answer

Firstly, we need to balance the equation:
LiS1U1P1 + ClS1U1P1 → LiCl(s) + S1S1P0

Using Hess's law, we can calculate the heat of solution of LiCl by adding the enthalpies of hydration of Li+ and Cl- ions and subtracting the lattice energy of LiCl.

Total heat of hydration = -865 kJ/mol

∆Hsoln (LiCl) = ∆Hhydration (Li+) + ∆Hhydration (Cl-) - lattice energy of LiCl

Thus, ∆Hsoln (LiCl) = -865 + (-869) - 828
                                = -2562 kJ/mol

Therefore, the correct answer is D) -37 kJ/mol.

Note: The negative sign indicates that energy is released (exothermic process) during the dissolution of LiCl.

The Total Heat of Hydration of 1 Mol of Gas