The solubility of KNO3 is 80g/100g water at 50 degrees and 10g/100g water at 0 degrees. The solubility of CuSO4 is 60g/100g water at 50 degrees and 20g/100g water at 0 degrees. A mixture contains 13.8g of KNO3 and 1.94g of CuSO4. A) Calculate the minimum mass of water that would dissolve the mixture at 50 degrees. B)the mixture is dissolved in the mass of water calculated in part (A) and then cooled to 0 degrees will any KNO3 crystallize out of the solution if so how many grams? What percent of the original amount of KNO3 of the original mixture has crysttallized out?

To answer Lu the answer is zero. There is no Cr2S3 in the above problem.

A. The easiest way is to calculate the minimum amount of H2O for BOTH solutes.
At 50C, solubility KNO3 is 80/100. We want to dissolve 13.8g KNO3. How much H2O do we need That is
100 g x 13.8/80 = about 17 g H2O but you need a more accurate answer.

The solubility of CuSO4 at 50 C is 60g/100. We want to dissolve 1.94g. How much water do we need? That's
100 x 1.94/60 = about 3 g H2O.
If we need about 3g H2O to dissolve the Cu and about 17g H2O to dissolve the KNO3, we will need about 17 to dissolve the mixture

B. Now we cool the mess to zero C. We have about 17 g H2O. Solubility at zero C for KNO3 is 10/100. How much will dissolve in the 17g. That's
10 x (17/100) = about 2g; therefore, 13.8-2 = 11.8 will crystallize. % recovery is about (11.8/13.8)*100 = ?%

The problem doesn't ask for it but how much of CuSO4 crystallizes to contaminate the KNO3? We had 1.94 and about 17g H2O so
20 x (17/100) = about 3g CuSO4 will dissolve in that 17 g H2O; we had only 1.94 initially; therefore, none of it crystallizes and the KNO3 is pure KNO3. The lesson here is that you can crystallize a mixture of solids and by using temperature and solvent the two separate the mixture and get at least one of them out pure.

For A wouldnt it be 20 g of water total instead of 17 g

To solve this problem, we need to consider the solubility of KNO3 and CuSO4 at different temperatures.

First, let's calculate the mass of water needed to dissolve the mixture at 50 degrees (Part A):

1. Calculate the mass of KNO3 and CuSO4 in the mixture:
Mass of KNO3 = 13.8g
Mass of CuSO4 = 1.94g

2. Determine the maximum amount of KNO3 that can be dissolved in 100g of water at 50 degrees:
Solubility of KNO3 at 50 degrees = 80g/100g water
Maximum mass of KNO3 that can be dissolved in 100g water = 80g

3. Determine the maximum amount of CuSO4 that can be dissolved in 100g of water at 50 degrees:
Solubility of CuSO4 at 50 degrees = 60g/100g water
Maximum mass of CuSO4 that can be dissolved in 100g water = 60g

4. Calculate the mass of water required to dissolve the mixture at 50 degrees:
Mass of water required for KNO3 = Mass of KNO3 / solubility of KNO3 at 50 degrees
Mass of water required for CuSO4 = Mass of CuSO4 / solubility of CuSO4 at 50 degrees

Mass of water required = Max(Mass of water required for KNO3, Mass of water required for CuSO4)

Now let's calculate the minimum mass of water required to dissolve the mixture at 50 degrees:

Mass of water required for KNO3:
= 13.8g / (80g/100g water)
= (13.8g * 100)/(80g)
= 17.25g

Mass of water required for CuSO4:
= 1.94g / (60g/100g water)
= (1.94g * 100)/(60g)
= 3.2333g

So, the minimum mass of water required to dissolve the mixture at 50 degrees is the maximum of these two values, which is 17.25g.

Now let's move on to Part B to determine if any KNO3 will crystallize out of the solution when cooled to 0 degrees:

1. Calculate the solubility of KNO3 and CuSO4 at 0 degrees:

Solubility of KNO3 at 0 degrees = 10g/100g water
Solubility of CuSO4 at 0 degrees = 20g/100g water

2. Determine the mass of KNO3 and CuSO4 in the mixture:

Mass of KNO3 = 13.8g
Mass of CuSO4 = 1.94g

3. Calculate the maximum mass of KNO3 and CuSO4 that can be dissolved in the minimum mass of water at 0 degrees:

Maximum mass of KNO3 that can be dissolved in 17.25g water = 17.25g * (10g/100g water)
Maximum mass of CuSO4 that can be dissolved in 17.25g water = 17.25g * (20g/100g water)

4. Compare the calculated maximum mass of KNO3 with the actual mass of KNO3 in the mixture (13.8g):

If the actual mass of KNO3 is less than the maximum mass that can be dissolved, the KNO3 will not crystallize out.

Difference in mass = Maximum mass of KNO3 - Actual mass of KNO3 = (17.25g * (10g/100g water)) - 13.8g

If the difference in mass is positive, it means that some KNO3 will crystallize out.

5. Calculate the percent of the original amount of KNO3 that has crystallized out:

Percent crystallized = (Difference in mass / Mass of KNO3) * 100

Now you can plug in the values and calculate the results.

WHAT IS THE MAXIMUM AMOUNT OF cR2S3 IN GRAMS OBTAINABLE