Answer:
0.54 g of Pb in 60 m³ of [Pb] = 9 ppb
Explanation:
We need to know, that ppb is a sort of concentration that indicates (in value of volume) ng / mL (ppb = parts per billion)
9 ppb means that 9 ng are contained in 1mL of solution
We know that 1mL = 1 cm³
Let's convert 60 m³ to cm³ → 60 m³ . 1×10⁶ cm³ / 1m³ = 6×10⁷ cm³
Then, we can make a rule of three:
1 cm³ has 9 ng of Pb
Therefore in 6×10⁷ cm³ we must have ( 6×10⁷ cm³ . 9ng) / 1 cm³ =
5.4×10⁸ ng
We convert ng to g → 5.4×10⁸ ng . 1 g / 1×10⁻⁹ ng = 0.54 g