Enthalpy of hydration
Enthalpy of hydration
Formula
ΔH°sol = ΔH°latt(dissociation) + ΔH°hyd(cation) + ΔH°hyd(anion)
Real World
When lithium chloride (LiCl) dissolves in water in chemical hand warmers, the large hydration enthalpy of the small Li⁺ ion outweighs the lattice enthalpy, making dissolution highly exothermic and releasing heat.
Exam Focus
State the sign and explain why — hydration enthalpies are always negative because ion–dipole bonds form; losing marks here is avoidable.
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