The chemical formula of the chelating agent Versence is `C_(2) H_(4) N_(2) (C_(2) H_(2) O_(2) Na)` If each mol of this compound could bind 1 mol of `Ca^(2+)`, what would be the rating of pure Versene, expressed as `mg CaCO_(3)` bound per `g`. Of chealting agent? `Ca^(2+)` is expressed in terms in terms of amount of `CaCO_(3)` it could form.
`[Mw "of vesene" = 380, Mw "of" CaCO_(3) = 100 g mol^(-1)]`

Explanation

For each mol of compound:
Weight of `CaCO_(3) = (1 mol Ca^(2+)) ((1 mol CaCO_(3))/(mol Ca^(2+)))`
`((100 g CaCO_(3))/(mol CaCO_(3))) ((10^(3) mg)/(g))`
`= (1 xx 1 xx 100 xx 10^(3))/(1) = 1.0 xx 10^(5)`
Weight of `CaCO_(3)//g` of versene `= (1.0 xx 10^(5) mg CaCO_(3))/(380 g "versene")`
`= 263 mg`