A sample of drinking water was found to be severely contaminated with chloroform (CHCl3). Supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
(i) Express this in percentage by mass.
(ii) Determine the molality of chloroform in the water sample.
A sample of drinking water was found to be severely contaminated with chloroform (CHCl3). Supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
(i) Express this in percentage by mass.
(ii) Determine the molality of chloroform in the water sample.
Part (i): Calculating the percentage by mass
ppm by mass is the amount of solute in 106g of solution.
Given:
Concentration =15ppm
Now, 106g of solution contains =15g of CHCl3
Hence; 100g of solution contain =15/106×100
=15×10−4=0.0015%
Part (ii): Calculating the molality of chloroform
Molar mass of chloroform =119.5g/mol
Mass of solvent =1000000−15=999985g
Molality=Molesofsolute/Mass of solvent×1000
m=15119.5×999985×1000
m=1.266×10−4m
Part (i): Calculating the percentage by mass
ppm by mass is the amount of solute in 106g of solution.
Given:
Concentration =15ppm
Now, 106g of solution contains =15g of CHCl3
Hence; 100g of solution contain =15/106×100
=15×10−4=0.0015%
Part (ii): Calculating the molality of chloroform
Molar mass of chloroform =119.5g/mol
Mass of solvent =1000000−15=999985g
Molality=Molesofsolute/Mass of solvent×1000
m=15119.5×999985×1000
m=1.266×10−4m
