Question

When KNO^3 is dissolved in water, the resulting solution is significantly colder than the water was originally.

(a) What conclusions can you draw about the intermolecular attractions involved in the process?

(b) Is the resulting solution an ideal solution?

Answer 1

The solution resulting from dissolving KNO3 in water is colder due to the endothermic nature of the process, indicating that the ionic bonds in solid KNO3 are stronger than their interaction with water. This also implies that the resulting solution is not an ideal solution as there is significant heat absorption.

Step-by-step explanation:

Dissolution of KNO3

When potassium nitrate (KNO3) is dissolved in water, the temperature of the solution decreases, indicating that the dissolution process is endothermic. This is because energy is absorbed to break the strong ionic bonds between the K+ and NO3- ions and to interact with water molecules. The energy required for this process comes from the thermal energy of the water, which results in a colder solution. The attraction between K+ and NO3- ions in solid KNO3 is stronger than the attraction between these ions and the surrounding water molecules.

Ideal solutions are characterized by the absence of any significant heat release or consumption during the formation of the solution. Since the dissolution of KNO3 is an endothermic process, where heat is absorbed, the resulting solution of KNO3 in water is not an ideal solution.