Understanding Solubility
* Solubility: The maximum amount of a substance (solute) that can dissolve in a given amount of solvent (water in this case) at a specific temperature.
* Saturation: A solution is saturated when it holds the maximum amount of solute at a given temperature. Any additional solute will not dissolve and will begin to crystallize.
Finding the Saturation Point
1. Solubility Curve: You'll need to consult a solubility curve for potassium nitrate. This curve shows the relationship between temperature and the amount of KNO₃ that can dissolve in 100 g of water.
2. Locate the Point: Find the point on the curve that corresponds to 30 g of KNO₃ dissolved in 100 g of water.
3. Read the Temperature: The temperature at that point is the temperature at which the solution becomes saturated.
Important Considerations
* Cooling: When you cool a saturated solution, the solubility of the solute decreases. This means less KNO₃ can stay dissolved at the lower temperature, and crystals will start to form.
* Supersaturation: It's possible to create a supersaturated solution where you have more solute dissolved than the solubility allows. This is unstable and crystals will readily form if you introduce a "seed" crystal or even a disturbance.
Example
Let's assume the solubility curve shows that at 20°C, 30 g of KNO₃ can dissolve in 100 g of water. This means:
* At 20°C, your solution is saturated.
* If you cool the solution below 20°C, the solubility decreases, and crystals will start to form.
To get a precise answer, you'll need to find the solubility curve for potassium nitrate.
