Your friend eats 50.0g tuna steak. You find out that the tuna is 0.001% (by mass) mercury. The lethal dose of mercury is 5.5x10^-3 mg of mercury. Should you take your friend to the hospital?
2 answers
50.0 x 1E-5 = ? grams. Multiply by 1000 to convert to mg. Compare with 5.5E-3.
Aren't we supposed to multiply 50.0g by 0.001? Where did 1E^-5 come from?