How does temperature generally affect the solubility of solids in water?

How does temperature generally affect the solubility of solids in water?

• A. Solubility generally increases with temperature
• B. Solubility generally decreases with temperature
• C. Temperature has no effect on solubility
• D. Solubility oscillates randomly with temperature

Answer: (A)

Solubility of solids in water generally rises with temperature because dissolving a solid usually requires energy to break the solid’s lattice and to hydrate the ions or molecules in water. If the dissolution process absorbs heat (positive enthalpy of solution), adding heat at higher temperatures makes it easier for more solid to dissolve, pushing the system toward the dissolved state before saturation. In other words, higher temperature supplies the energy needed to overcome lattice forces, so more solute can stay dissolved. There are exceptions, though: some solutes dissolve with the release of heat (negative enthalpy of solution), so their solubility can decrease as temperature increases. Overall, the common trend is increased solubility with rising temperature, with those notable exceptions.

Solubility of solids in water generally rises with temperature because dissolving a solid usually requires energy to break the solid’s lattice and to hydrate the ions or molecules in water. If the dissolution process absorbs heat (positive enthalpy of solution), adding heat at higher temperatures makes it easier for more solid to dissolve, pushing the system toward the dissolved state before saturation. In other words, higher temperature supplies the energy needed to overcome lattice forces, so more solute can stay dissolved. There are exceptions, though: some solutes dissolve with the release of heat (negative enthalpy of solution), so their solubility can decrease as temperature increases. Overall, the common trend is increased solubility with rising temperature, with those notable exceptions.