The solubility of a compound in water is 6.8g/100ml at 25°c calculate the amount of water required to crystallize 10grams of the compound if the pure compound is collected at 25°c what is the maximum possible yield percent?
I'm having a little trouble knowing exactly what you want; however, I think your compound has a solubility of 6.8 g/100 and you want to collect 10.0 g.
The solubility is 5.8 and you want to collect 10.0 so you must have enough solution that contains 6.8 + 10.0 = 16.8 g of the compound. How much solution must you start with? That's 100 x 10.0/6.8 = 247 mL. Now if you evaporate 147 mL of the 247 mL to leave you with 100 mL of solution, you will get 16.8-6.8 or 10.0 g of the compound.
% recovery is (10.0/16.8)*100 =? or about 60%.
Notice that you have not made it clear as to the final volume to be used and I've assumed 100 mL; however you could use a smaller final volume. For example, if you chose 50 mL final volume the numbers are
6.8 g/100 mL = 3.4 g/50 mL.
You will then need an inital volume that will accommodate 3.4g + 10.0 = 13.4.
Then 100 x (13.4/6.8) = 197 mL of solution.
Evaporating to 50 gives you 13.4-3.4 = 10.0 g
% = (10/13.4)*100 = about 75%.
Finally, if you want to reduce the final volume to zero mL to get all 10.0 how much initial solution to you need? That's 100 x (10.0/6.8) = 147. Now you have 10.0 g of the compound in solution, evaporate all of the water and you will collect alol 10.0 g which will be 100%, at least theoretically.
I hope one of these solutions is what you are looking for.If not, clarify and we can go at it again.
To calculate the amount of water required to crystallize 10 grams of the compound, we need to use the solubility information provided.
The given solubility of the compound is 6.8g/100ml at 25°C. This means that 6.8 grams of the compound can dissolve in 100 ml of water at that temperature.
To find the amount of water required to dissolve 10 grams of the compound, we can set up a proportion using the given solubility:
(6.8 grams / 100 ml) = (10 grams / x ml)
Cross-multiplying, we get:
6.8x = 1000
x = 1000 / 6.8
x ≈ 147.06 ml
Therefore, approximately 147.06 ml of water is required to dissolve 10 grams of the compound.
Now, to calculate the maximum possible yield percentage, we need to compare the actual yield to the theoretical yield. The theoretical yield is the maximum amount of pure compound that could be obtained from the given amount.
In this case, the given amount is 10 grams, so the theoretical yield is 10 grams.
The actual yield is the amount of pure compound obtained after the crystallization process. Since we need 147.06 ml of water to dissolve 10 grams, we need to consider the volume change due to the compound's solubility. If the volume decreases during crystallization, the actual yield may be less than the initial amount of the compound.
Assuming the volume remains constant during the crystallization process, the actual yield can be considered as 10 grams.
The yield percentage is then calculated using the formula:
Yield percentage = (Actual yield / Theoretical yield) x 100
Plugging in the values, we get:
Yield percentage = (10 grams / 10 grams) x 100
Yield percentage = 100%
Therefore, the maximum possible yield percentage in this case is 100%.