A 0.700 g unknown mixture with CaCl2 reacts with aqueous sodium phosphate to give 0.425 g Ca3(PO4)2. Show calculation for the percentage CaCl2?

The percentage CaCl₂ : 65.14%

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

Reaction

3CaCl₂+2Na₃PO₄⇒Ca₃(PO₄)₂ + 6NaCl

mol Ca₃(PO₄)₂(MW=310.18 g/mol) :

mol ratio CaCl₂ : Ca₃(PO₄)₂ = 3 : 1, so mol CaCl₂ :

mass CaCl₂ (MW=110.98 g/mol) :

The percentage CaCl₂ :

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.