100g of a saturated solution of KNO3 was cooled from 80 degrees to 50 degrees. What mass of KNO3 would be expected to crystallise out of the solution?
Few people memorize solubility tables. Surely you have a graph or table giving the solubility of KNO3 vs temperature. If you will post the solubility in those tables/graph at 80 C and 50 C I can show you how to do this.
KNO3 solubility at 80 C is 180g/100g
KNO3 solubility at 50 C is 78g/100g
To determine the mass of KNO3 that would crystallize out of the solution, we need to find the solubility of KNO3 at 80 degrees and 50 degrees. The solubility of a substance is the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature.
We can look up the solubility values of KNO3 at different temperatures in a solubility table or use a solubility curve for KNO3.
Let's assume that at 80 degrees, the solubility of KNO3 is 150g/100g of water, and at 50 degrees, the solubility is 50g/100g of water.
To find the amount of KNO3 that would crystallize out, we need to determine the difference between the amount of KNO3 dissolved at 80 degrees and the amount dissolved at 50 degrees.
First, calculate the initial amount of KNO3 dissolved at 80 degrees:
100g of solution x (150g/100g) = 150g of KNO3 dissolved at 80 degrees.
Next, calculate the amount of KNO3 that remains dissolved at 50 degrees:
100g of solution x (50g/100g) = 50g of KNO3 dissolved at 50 degrees.
Finally, subtract the amount of KNO3 dissolved at 50 degrees from the initial amount dissolved at 80 degrees:
150g - 50g = 100g of KNO3 that crystallizes out of the solution.
Therefore, 100g of KNO3 would be expected to crystallize out of the solution when cooled from 80 degrees to 50 degrees.