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(Solved): A 282.5-g sample of ground water is analyzed for calcium. The Ca2+ in the sample is first precipitat ...
A 282.5-g sample of ground water is analyzed for calcium. The Ca2+ in the sample is first precipitated and filtered-off as NH4CaPO4·7H2O. This precipitate is dried and heated, releasing water and ammonia to yield anhydrous calcium pyrophosphate (Ca2P2O7). The mass of Ca2P2O7 obtained is 0.0869 g.
Give the calcium content of the ground water in parts per million (to three significant figures).
SOLUTION : To determine the calcium content of the ground water in parts per million (ppm), we need to calculate the mass of calcium (Ca) in the sample and then convert it to ppm.
Calculate the moles of Ca2P2O7 obtained:Mass of Ca2P2O7 = 0.0869 g