Question

A waste tank containing a liquid of Bromide at a concentration of 1500 mg/L was released into a shallow disposal pit which is overlain by 2 m thick aquifer at a discharge rate of 4 m3/day for many years. The average linear groundwater velocity is 0.2 m/day. Also, assume that transverse dispersion in 20% of the longitudinal dispersion. Assume that disposal pit is located at xo = 0 and yo = 0. What would be the concentration of Bromide in a monitoring well located at x = 150 m and y =16 m? For longitudinal dynamic dispersivity (αL), use

αL = 0.83 (Log (L))2.414. For Bessell function of the second order, use Appendix B or use besselk(1,x) from the Matlab command prompt.

Answer 1

There is to calculate the concentration of this solution in mol/L

C=n/V=mol/L

The data are

Bromide = 1500 mg =1.5 gram

volume= 1 L

The problem gives the Volume there is to find the number of moles,n

n from the stochiometry of molarity is equal to

n=m/M

where m is the mass in g and M the molecular weight .

we have m,we must calculate M for Br2

The periodic table provides the info

MBr=79.904

The formula is Br =79.904 amu

n=m/M

=1.5/79.904=0.0188 moles

Finally the concentration will be given after volume in L

C=n/V =0.0188/1 =0.0188 mol/L