Question
Question: Find the solubility of $KNO_3$ at $20^\circ C$, when the mass of the empty dish is 50 g, the mass of...
Find the solubility of KNO3 at 20∘C, when the mass of the empty dish is 50 g, the mass of dish and solution is 65 g, while the mass of dish and residue is 54.3 g.

40.2 g per 100 g of water
Solution
The solubility of a substance is the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature, expressed as grams of solute per 100 grams of solvent.
Given:
- Mass of empty dish = 50 g
- Mass of dish and solution = 65 g
- Mass of dish and residue (KNO3) = 54.3 g
1. Calculate the mass of the solution:
Mass of solution=Mass of dish and solution−Mass of empty dish
Mass of solution=65g−50g=15g
2. Calculate the mass of the solute (KNO3):
Mass of KNO3=Mass of dish and residue−Mass of empty dish
Mass of KNO3=54.3g−50g=4.3g
3. Calculate the mass of the solvent (water):
Mass of solvent=Mass of solution−Mass of solute
Mass of solvent=15g−4.3g=10.7g
4. Calculate the solubility of KNO3:
Solubility=(Mass of waterMass of KNO3)×100
Solubility=(10.7g4.3g)×100
Solubility≈40.2g per 100 g of water