A dioxin-contaminated water source contains 0.085% dioxin by mass. How much dioxin is present in 2.5 L of this water? (Assume that the density of the solution is 1.01 g/mL.)
Solution: Here, we are going to calculate the mass of dioxin present in 2.5 L of a dioxin- contaminated water solution containing 0.085 % dioxin by mass.
Step1:
The mass percentage of a component of a solution is defined as:
Mass of the component in the solution
Mass % of a component = ----------------------------------------------------- × 100 ---(1)
Total mass of the solution
Step2:
Again, density may be defined as mass per unit volume.
Thus,
d = m / v
Here, density of the solution = 1.01 g/mL
Volume of the solution = 2.5 L = 2.5 x 1000 mL = 2500 mL [1 L = 1000 mL]
Therefore, mass of the solution = density x volume
= (1.01 g/mL) x 2500 mL
= 2525 g
Step3:
Mass % of dioxin in the solution = 0.085 %
Mass of the solution = 2525 g
Substituting the values in equation (1), we get,
0.085 = (mass of dioxin in solution / 2525 g) x 100
0.085 / 100 = mass of dioxin in solution / 2525 g
0.00085 x 2525 g = mass of dioxin in solution.
2.146 g = mass of dioxin in solution.
Thus, 2.146 g of dioxin is present in 2.5 L of a dioxin- contaminated water solution containing 0.085 % dioxin by mass.
--------------------------------
