The solubility of acetanilide in hot water (5.5 g/100 mL at 100C) is not very great, and its solubility in cold water (0.53 g/100 mL at 0C) is significant. What would be the maximum theoretical percent recovery from the first recrystallization of 0.5 g of acetanilide from 100 mL of water (assuming the solution is chilled to 0C)?
I might argue with the use of the words "not very great" and "significant."
How much H2O is needed to dissolve 0.50 g acetanilide? That's
100.0 mL x (0.5/5.5) = 9.09 mL.
How much will we lose on cooling that to zero C? That's
0.530 x (9.09/100) =0.048.
%recovery is (0.500-0.048)/0.500]*100 = ?
yes
To calculate the maximum theoretical percent recovery from the first recrystallization of acetanilide, we need to determine the maximum amount of acetanilide that can dissolve in the chilled water solution and compare it to the initial amount of acetanilide used.
First, let's calculate the maximum amount of acetanilide that can dissolve in 100 mL of chilled water at 0°C. From the given solubility data, we know that the solubility of acetanilide in cold water is 0.53 g/100 mL at 0°C. Therefore, the maximum amount of acetanilide that can dissolve in 100 mL of chilled water is:
0.53 g/100 mL x 100 mL = 53 g
However, we only have 0.5 g of acetanilide initially, so we can only dissolve 0.5 g in the chilled water solution.
Now, let's calculate the percent recovery. The percent recovery is calculated by dividing the actual amount of acetanilide recovered by the maximum amount that could have been recovered, and then multiplying by 100.
Actual amount of acetanilide recovered = 0.5 g
Maximum amount of acetanilide that could have been recovered = 0.5 g
Percent recovery = (0.5 g / 0.5 g) x 100 = 100%
Therefore, the maximum theoretical percent recovery from the first recrystallization of 0.5 g of acetanilide from 100 mL of water, assuming the solution is chilled to 0°C, is 100%.