[gingi]

Hi guys.
I'm having some problems solving this problems. Help would be appreciated !

The distribution coefficient, k = (conc. i ligroin/conc/ in water) between ligroin and water for solute A is 7.5. What weight of A would be removed from a solution og 10 g of A in 100 mL of water by a single extraction with 100 mL of ligroin ?
What weight of A would br removed by four successive extractions with 25 mL portions of ligroin ?
How much ligroin would be required to remove 98.5% of A in a single extraction ?

I simply don't have any idea how to solve it. thanks again !
G

[Dude]

This type of calculation is typically covered in an Analytical Chemistry course in the book chapter "Analytical Separations, separation by extraction".  There is a page or two algebra workup in the book that I have (Ch 24, Analytical Chemistry:  An Introduction, 5th ed, Skoog, Holler, West) followed by an example.