<p>A lake has .4 micrograms Hg (mercury)/ mL . The lake has a surface area of 100 mi^2 and a depth of 20 ft. How many kilograms of mercury are in the lake?</p>
<p>Since only one sig fig is apparent, I keep getting 6 x 10^5, but Zumdahl says it is 7 x 10^5. The exact answer I got is 63xxx (left two digits I definitely remember). </p>
<p>Can someone verify this conversion?</p>