A hard-water solution contains 4.8 g of calcium chloride. How much sodium phosphate in grams should be added to the solution to completely precipitate all of the calcium

4.7 g

Explanation:

The reaction that takes place is:

First we convert 4.8 g of CaCl₂ into moles, using its molar mass:

Then we convert CaCl₂ moles into Na₃PO₄ moles, using the stochiometric coefficients of the balanced reaction:

Finally we convert 0.0288 moles of Na₃PO₄ into grams, using its molar mass:

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements