Question

If the heat of solution is large and endothermic, then the amount of energy it costs to separate the ions is (less/greater) than the energy released from hydrating the ions?

Answer 1

If the heat of solution is large and endothermic, it implies that the energy required to separate the ions (lattice energy) is greater than the energy released during the hydration of ions, resulting in an overall endothermic process.

Step-by-step explanation:

If the heat of solution is large and endothermic, then the amount of energy it costs to separate the ions is greater than the energy released from hydrating the ions. To understand this process, we consider the enthalpy changes that accompany the formation of a solution. There are three steps to consider:

• Step 1: Separating solvent particles (energy required, endothermic).
• Step 2: Separating solute particles, or the lattice energy of the ionic solid (energy required, endothermic).
• Step 3: Hydration of the ions, or solute-solvent interactions (energy released, exothermic).

When the lattice energy (AH2) is greater than the energy released during hydration (AH3), the overall process requires more energy to take place than it releases, leading to an endothermic solution formation.