1. In 1981, concentrations of Pb, Cu, and Mn in rainwater collected in Min-neapolis were found to be 9.5, 2.0, and 8.6 µg/L, respectively. Express these concentrations as nmole/L, given that the atomic weights are 207,63.5, and 55, respectively.
2. The dissolved oxygen (DO) profile in a biological reactor (i.e., aeration tank) at a domestic wastewater-treatment plant is OS mg/L in the anoxic zone and 8 mg/L near the end of the 108-ft-long tank. What are these two DO concentrations in units of
(a) ppm,
(b) moles/L?