posted by Sandy on .
Health regulations stipulate that the amount of arsenate in drinking water be no grater than 10 parts per billion (ppb) arsenic. If the arsenic present is arsenate, AsO4^-3, what mass of sodium arsenate would be present in a 1.00 L sample of drinking water that just meets the standard?
There are a few conversions that are good to remember.
%, of course, is pph (parts per hundred) = 1 g/100 g
1 ppt = 1g/1000g which is very close to 1 g/L.
1 ppm = 1 mg/L
1 ppb = 1 ug/L
1 ppb = 1 ug As/L
Convert 1 ug As to ug Na3AsO4
1 ug As x (molar mass Na3AsO4/atomic mass As) = ? ug Na3AsO4.