Recitation Assignment 3
Due at the end of class
Recitation Problem:
You are scuba-diving in a karstic cave system near a landfill and you come across a large,
trapped air bubble. You sample the bubble with your portable gas chromatograph
and find that the bubble contains benzene at a partial pressure of 0.12 atm (benzene: C6H6 is
a common carcinogenic organic pollutant). Assume STP (i.e. Temperature is 25 deg C and
total pressure in the bubble is 1 atm.
KH for benzene is 5.5 atm*L*mol-1 at 25 deg C
(a) What is the concentration of benzene in the bubble in ppmv?
(b) Assuming the bubble is in equilibrium with the water,
what is the concentration in mg/l of benzene in the cave water?
(c) How does this compare to the MCL (EPA maximum concentration levels
for drinking water) MCL for benzene is 5 µg/l?
Problem adapted from Appelo, C.A., Postma, D., (2005), p.