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Your goal here is to calculate the solubility of water in 1-butanol. The known solubility of water in 1-butanol is 22 g H2O/100 mL 1-butanol at 20oC.
In the first part of the experiment, you placed 10.0 mL each of water and butanol in a graduated cylinder, mixed the two substances thoroughly, and allowed them to separate back into layers. If the two substances were immiscible (like water and hexane), you'd have observed complete separation back into the original 10.0 mL layers. In this case, the substances are partially soluble in one another, and the solubilities are not equal (why not?)
Table 1 in the report should show the volumes and compositions of the phases before and after mixing:
Table 1. Volume and composition of layers before and after mixing.
| Layer | Composition before mixing | Volume before mixing (mL) | Composition after mixing | Volume after mixing (mL) |
| Bottom | Water | 10.0 | water saturated with 1-butanol | 9.0 |
| Top | 1-Butanol | 10.0 | 1-butanol saturated with water | 11.0 |
During the procedure, you measured the volume of butanol recovered after salting-out the water from the top layer (butanol saturated with water.) You know the original volume of this layer (it's in Table 1), and you measured the amount of butanol recovered from this layer, so the difference must correspond to the amount of water dissolved in the butanol. Calculate the solubility of water in butanol and compare it to the accepted value given above.
You can also calculate the total amount of butanol recovered from the salting-out portion of the experiment. You originally separated the two layers (water sat. with butanol and butanol sat. with water), and you salted out the top layer and measured how much water was dissolved in the butanol. You retained the bottom layer (water sat. with butanol), and you salted the water out of this layer, and measured the amount of butanol recovered. You added this to the butanol recovered earlier - this should add to 10 mL, right? If it doesn't add to 10 mL, discuss this in your error analysis.