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A sample of drinking water was found to be serverly contaminated with chloroform, CHCl_(3), supposed to be carcinogen. The level of contamination was 15 ppm (by mass). (i) Express this in percent by mass. (ii) Determine the molality of chloroform in the water sample. |
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Answer» SOLUTION :15 ppm means 15 PARTS in million `(10^(6))` parts by mass in the solution `therefore"% bymass "=(15)/(10^(6))xx100=15xx10^(-4)` Taking 15 g chloroform in `10^(6)g` of the solution, mass of solvent `~=10^(6)g` Molar mass of `CHCl_(3)=12+1+3xx35.5="119.5 g mol"^(-1)` `therefore"Molality"=(15//119.5")/(10^(6))xx1000=1.25xx10^(-4)m.` |
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