it is estimated that uranium is relatively common in the earth's crust, occurring in amounts of 4 g/metric ton. a metric ton is 1000kg. at this concentration, what mass of uranium is present in 1.0 mg of earth's crust?
math/chem - MathMate, Monday, August 23, 2010 at 10:30pm
1.0 mg * 4 g / 1000*1000g
=0.000 004 mg.