Chapter 13 - The Chemistry of Solutes and Solutions - Questions for Review and Thought - Topical Questions - Page 605b: 23

Endothermic.

$\Delta_{r}H_{solution}=-lattice\,energy+ total\, enthalpy\,of\, hydration\,of\,ions$ $=-(-2961\,kJ/mol)+(-2948\,kJ/mol)$ $=13\,kJ/mol$ As $\Delta_{r}H_{solution}$ is greater than 0, this is an endothermic process.