A compound whose solubility in ethanol is 4.24g/100ml at 78c and .3 g/100ml at 0c is recrystalize by heating it at 78 and then cooling it to 0c. If we are to recrystalize a .5g of this compound in a 10ml of solvent, what is the maximum possible % recovery?
I think i solve my own question, not sure if I am correct, someone please verify it for me.
Since 4.24g/100ml then .424g/10ml, thus 0.5-.424g (dissociated)=.076g (lost during heating).
0.3g/100ml is 0.03g/10ml at 0c during cooling
Then 0.424g-0.03g=0.394g thus, this is the remainding compound.
And %Recovery=0.394/0.5g*100=78.8%
Can someone confirm that I got this correct?
To determine the maximum possible percentage recovery, we need to calculate the maximum amount of compound that can be recovered from the 0.5g dissolved in the solvent.
Step 1: Calculate the solubility of the compound at 78°C.
Given that the solubility is 4.24g/100ml at 78°C, we can convert this to grams per milliliter (g/ml):
4.24g/100ml = 0.0424g/ml
Step 2: Calculate the maximum volume of the solvent needed to dissolve 0.5g of the compound.
To dissolve 0.5g of the compound, divide the mass by the solubility at 78°C:
0.5g / 0.0424g/ml = 11.8 ml
Step 3: Determine the maximum amount of compound that can be recovered by cooling to 0°C.
Given that the solubility is 0.3g/100ml at 0°C, we can convert this to grams per milliliter (g/ml):
0.3g/100ml = 0.003g/ml
Subtracting the solubility at 0°C from the solubility at 78°C gives us the difference in solubility:
0.0424g/ml - 0.003g/ml = 0.0394g/ml
Multiply the difference in solubility by the maximum volume of the solvent:
0.0394g/ml * 11.8 ml = 0.464g
Step 4: Calculate the percentage recovery.
Divide the amount of compound recovered (0.464g) by the initial amount dissolved (0.5g), then multiply by 100 to get the percentage:
(0.464g / 0.5g) * 100 = 92.8%
Therefore, the maximum possible percentage recovery is 92.8%.