1.Write out the net equation for the dissolution of the ionic compound KNO3. 2. Do you expect the dissolution of KNO3 to be endothermic or exothermic?
3. Do you expect the dissolution of KNO3 to have a positive or negative ?

1. KNO3(s) > K^+(aq) + NO3^-(aq)

2. The dissolution is endothermic

3. The sign of the enthalpy of dissolution is positive

Explanation:

The sign of the enthalpy of dissolution depends on the hydration energy and the lattice energy.

For KNO3, the hydration energy is less than the lattice energy hence the dissolution is endothermic and the enthalpy of dissolution is positive.