Final answer:
A saturated solution of KNO₃ will experience recrystallization as it cools from 80 degrees celsius to room temperature, as the solubility decreases with temperature.
Step-by-step explanation:
When a saturated solution of KNO₃ at 80 degrees celsius is left to cool to room temperature, the solubility of the solute decreases. Since the solubility curve for KNO₃ is very steep, a decrease in temperature can lead to recrystallization of the solute. At 80 degrees celsius, the solution is saturated, but as it cools down to room temperature, the excess solute that can no longer remain dissolved will start to crystallize out of the solution. This occurs because the solubility of KNO₃ is highly dependent on temperature; as the temperature drops, the solution can hold less of the solute in solution, leading to crystal formation.