Answer:
Approximately 8.8 grams of solid KNO3 will precipitate from the solution when it's cooled from 50 degrees Celsius to 20 degrees Celsius.
Step-by-step explanation:
The solubility of a solid in a liquid typically decreases as the temperature decreases. As a result, when a saturated solution is cooled, some of the solid may precipitate out of the solution.
The solubility of potassium nitrate (KNO3) in water at 20 degrees Celsius is around 42 grams per 100 milliliters of water. At 50 degrees Celsius the solubility is around 86 grams per 100 milliliters of water.
To find the mass of solid that will precipitate, we can use the difference between the solubility of KNO3 at 20 degrees Celsius and at 50 degrees Celsius.
At 20 degrees Celsius, the solubility of KNO3 is 42 g/100 mL, and at 50 degrees Celsius, the solubility is 86 g/100 mL.
So, the difference between the solubility of KNO3 at 20 degrees Celsius and at 50 degrees Celsius is 86 - 42 = 44 grams per 100 milliliters.
Since we have 20 mL of a saturated solution, we can calculate the mass of the precipitate by multiplying the difference in solubility by the volume of the solution:
44 g/100 mL * 20 mL = 8.8 grams.
So, approximately 8.8 grams of solid KNO3 will precipitate from the solution when it's cooled from 50 degrees Celsius to 20 degrees Celsius.
Please note that this is an approximate calculation and the actual amount of precipitate may vary depending on other factors such as impurities and the specific conditions of the experiment.