On the basis of the solubility curve for KNO3 what type of substance would you expect KNO3 to be?

ionic, at least between the K and the NO3^- part.

To determine the type of substance based on the solubility curve for KNO3, you would need to analyze the relationship between temperature and solubility.

Solubility refers to the ability of a substance to dissolve in a particular solvent at a given temperature. A solubility curve shows the variation in solubility of a substance as the temperature changes.

In the case of KNO3 (potassium nitrate), if the solubility of KNO3 increases as the temperature increases, it indicates that KNO3 is a solute that is more soluble in hot water.

Based on the common characteristics of substances, KNO3 is an example of a solid solute that dissolves in a liquid solvent (water in this case).