[kuttaman]

Assuming the following values, calculate how much caffeine should be obtained :  Kp (CH2Cl2/water) = 3.0; 20 mL for the water layer with 25 mg of caffeine in it before extraction and 2 x 6 mL for the CH2Cl2 layers.

Work done so far.

kp= [XDCM] / [XW] = ( mDCM / 6 mL)  / (MW / 20) = 3.0

Now im confused on what to do with the 25 mg caffeine

[Hunter2]

k = cI/cII = mI /VI /(mII/ VII) = mI *vII /(mII *VI)

Your 25 mg is first in 20 ml water, after first extraction its distribute 1:3 in methylen chloride