A packed chromatographic column is a piece of tubing through

which a carrier fluid flows; it is packed with a porous medium that

has a significant tendency to sorb chemicals of interest. A pulse of

a mixture of chemicals is injected into one end of the column, and

each chemical then moves at a velocity according to its distribution

coefficient between the meving fluid and the porous medium.

Note that this is identical to a sorbing solute being transported by

groundwater.

The elumn has the following characteristics:

$0\mathrm{.}1g$ of each of chemicals A and B are instantaneously and

simultaneously injected.

a$.$ How long does it take the center of mass of chemical A to travel

$200cm$ along the column?

b$.$ How long does it take the center of mass of chemical B to travel

$200cm$ along the column?

c$.$ What is $C_{\text{m}\text{a}\text{x}}$ and the spatial distribution of chemical A after its

center of mass has traveled $2m?$ Assume that the only mixing

process is mechanical dispersion.