##### What mass of sodium arsenate would be present?

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If this arsenic is present as arsenate, , what mass of sodium arsenate would be present in a 1.80

sample of drinking water that just meets the standard? Parts per billion is defined on a mass basis

Oct 19th, 2017

The problem this causes in in determining the mass-to-mass ratio (the gravimetric ratio) between the salt and the elemental forms of As.
I'll use Na2HAsO4.7H2O in the calculation, but you can follow the same procedure with any of the salt formulae.
1 mole of Na2HAsO4.7H2O: contains 1 mole of As
Set up the gravimetric factor using this molar relationship.
(1 mole of Na2HAsO4.7H2O)/(1 mole of As) = ((1 mole of Na2HAsO4.7H2O)*(312.01 g/mol))/((1 mole of As)*(74.92 g/mol)) = (312.01 g Na2HAsO4.7H2O)/(74.92 g As) = (4.16 g Na2HAsO4.7H2O)/(1 g As)

For further info, check out the link

Jan 18th, 2015

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Oct 19th, 2017
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Oct 19th, 2017
Oct 20th, 2017
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