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## Homework Statement

## Homework Equations

R

_{d}= retardation factor = (1 + (ƥ

_{b}K

_{d}/ n))

log(K

_{oc}) = -0.55logS + 3.64

K

_{d}= K

_{oc}*f

_{oc}

## The Attempt at a Solution

Part C is the only part I feel sure on. I simply plugged 1480 mg/L into the log(K

_{oc}) equation above to solve for K

_{oc}. Then I multiplied K

_{oc}by the f

_{oc}given in the problem statement to obtain K

_{d}. Finally, I plugged K

_{d}in the R

_{d}equation above along with the bulk density of the soil and the soil porosity given, and solved. Seems straight forward enough.

Part A is simply a concept-type question, but I do not know how to relate coefficients to this type of graph shown. Since there is no textbook for the class, I have no way to confirm if I'm right or not in my current thinking. I answered that the partition coefficient would be biggest for solute C and smallest for solute A, because a small partition coefficient would imply it dissolves in water more easily, shown by the graph for solute A reaching equilibrium the quickest. Am I correct here?

Part B is the oddest for me. At first I thought it was giving me the R

_{d}of solute A so that I could plug in and solve for K

_{d}, then use that K

_{d}for the solute B to solve for its R

_{d}. However, plugging in 1 for R

_{d}gives a K

_{d}of 0, so it must not be the right method. So, I simply compared the times it took solute A and solute B, and multiplied solute A's R

_{d}by the same factor. So since 3.5 hours is 1.75x more than 2 hours, I did (1 * 1.75) = 1.75 for the R

_{d}of solute B. I'm sure this method is totally wrong, but I have no references to find the right way, so any help would be much appreciated.

One thing that immediately lets me know I'm wrong somewhere is that I never used the 20 cm length given in the problem statement. Is this somehow used to find solute B's R

_{d}?