An instrument used to detect metals in drinking water can detect as little as 1 µg of mercury in 1 L of water. Mercury is a toxic metal; it accumulates in the body and is responsible for the deterioration of brain cells. Calculate the number of mercury atoms you would consume if you drank 1 L of water that contained 1 µg of mercury. (The mass of one mercury atom is 3.3 x 10^-22 g.)

Answer 1

How many mols is in 1 ug Hg metal?
mols = g/atomic mass = 1E-6 g/200.61 g/mol = ? = about 3.6E-7
Then 1 mol contains 6.022E23 atoms so 3,6E-7 moles will contain ........atoms.