Question

you take .5g of a compound and add it to tube along with 10.0 ml of water and 5.8 ml methylene chloride. after shaking this sample and allowing the layers to separate, you collect the methylene chloride layer. after drying and evaporating the organic layer, you determined that 0.42 g of compound was in this layer. determine the partition coefficient

Answer 1

Volume of water = 10 ml

Volume of methylene chloride = 5.8 ml

Mass of compound = 0.5 g

Mass of compound in organic layer after evaporation = 0.42 g

Mass of compound in aqueous layer after evaporation = 0.5 g-0.42 g = 0.08 g

Partition coefficient, P or Kc = Ratio of solubility of compound in organic phase and solubility of compound in aqueous phase at constant temperature.

P = solubility of compound in organic phase/solubility of compound in aqueous phase

Solubility of compound in organic phase = mass of compound in organic phase / Volume of organic phase

Solubility of compound in aqueous phase = mass of compound in aqueous phase / Volume of aqueous phase

P = 0.42 g/5.8 ml of organic phase / 0.08 g/10 ml of aqueous phase = 0.0724/0.008 = 9.05

Partition coefficient, P = 9.05