A 355g sample of a saturated solution of KNO3(s) in water is prepared at 25.0 degrees C.

If 50g H2O is evaporated from the solution at the same time as the temperature is reduced from 25.0 to 0.0 degrees C, what mass of KNO3(s) will recrystallize?

i have no idea where to start.. it refers me to a graph which shows the g solute/100g h2o vs temperature.. and it looks like there is 15g kno3/100g h2o at 0 degrees and 37ish g at 25 degrees.. but i don't know what to do with this information

I don't have a chart so I can't help you. I posted something about the 1.48 m problem. Take a look and see if it looks reasonable.

calculate of mass of KNO3 precipitated when a saturated solutions is coold from 82°c to 25°c

To solve this problem, we can use the solubility curve for KNO3(s) in water. The solubility curve represents the maximum amount of solute that can dissolve in a given amount of solvent at different temperatures.

Here's how we can approach the problem:

1. Determine the initial mass of KNO3(s) in the saturated solution:
- The problem states that the sample is a saturated solution, which means that it contains the maximum amount of solute (KNO3) dissolved in the solvent (water) at 25.0°C.
- From the solubility curve, we can see that at 25.0°C, the solubility of KNO3 is approximately 37g/100g of water.
- Therefore, using simple proportion, we can find the initial mass of KNO3(s) in the solution:
Initial mass of KNO3 = (37g/100g) x (355g) = 131.35g

2. Calculate the final mass of water after evaporation:
- The problem states that 50g of water is evaporated from the solution. Therefore, the final mass of water can be calculated by subtracting the evaporated mass from the initial mass:
Final mass of water = 355g - 50g = 305g

3. Determine the solubility of KNO3(s) at 0.0°C:
- Referring to the solubility curve, we can find the solubility of KNO3 at 0.0°C, which is approximately 15g/100g of water.

4. Calculate the maximum mass of KNO3(s) that can be dissolved in the final mass of water (305g) at 0.0°C:
- Using the proportion, we can calculate the maximum mass of KNO3 at 0.0°C as follows:
Maximum mass of KNO3 = (15g/100g) x (305g) = 45.75g

5. Calculate the mass of KNO3 that will recrystallize:
- The mass of KNO3 that will recrystallize is the difference between the initial mass (131.35g) and the new maximum solubility at 0.0°C (45.75g):
Mass of KNO3 recrystallized = Initial mass of KNO3 - Maximum mass of KNO3 at 0.0°C
= 131.35g - 45.75g
= 85.6g

Therefore, approximately 85.6 grams of KNO3 will recrystallize when 50 grams of water is evaporated from the saturated solution of KNO3 in water at 25.0°C, and the temperature is reduced to 0.0°C.