Question

Toxic chemicals in drinking water usually are reported and a safety level specified in units of parts per million (ppm) by mass. What is the molar concentration of arsenic in a water sample that has 1ppm arsenic (As)?

DrBob222
1 ppm = 1 mg/L and although that isn't by mass at 1 ppm by mass and by volume is essentially the same.
So you have 1 mg/L
Convert 1 mg to mols As.


* I got 1.33 x 10^4.

Answer 1

I didn't obtain that answer.
Convert mg to grams, then convert grams As/L to mols As/L and that is M. Does it sound reasonable to you that a small concentration (like 1 ppm) is more than 10,000 M. I don't think so.