* Endothermic Dissolution: This means the process absorbs heat from the surroundings, making the solution feel colder. This happens when the energy required to break the bonds between the solid's molecules is greater than the energy released when the solid molecules interact with water molecules. Examples include:
* Dissolving ammonium nitrate (used in cold packs)
* Dissolving potassium chloride
* Exothermic Dissolution: This means the process releases heat into the surroundings, making the solution feel warmer. This happens when the energy released by the interaction between the solid molecules and water molecules is greater than the energy needed to break the bonds within the solid. Examples include:
* Dissolving sodium hydroxide
* Dissolving sulfuric acid
In summary: The enthalpy change (heat change) during dissolution is determined by the balance between the energy needed to break the bonds in the solid and the energy released when the solid interacts with water.
