Question

What mass of sodium phosphate is necessary in order to produce 5.00 g of calcium phosphate
according to the reaction:
2Na3PO4 + 3CaCl2--> 6NaCl + Ca3(PO4)2
a)18.92 g Sodium Phosphate
b)1.32 g Sodium Phosphate
c)5.29 g Sodium Phosphate
d)7.13 g Sodium Phosphate

Answer 1

Answer:

The answer to your question is the letter C

Explanation:

mass of Na₃PO₄ = ?

Ca₃(PO₄)₂ = 5 g

Balanced chemical reaction

                2Na₃PO₄  +  3CaCl₂  ⇒  6NaCl  + Ca₃(PO₄)₂

Process

1.- Calculate the molar mass of Sodium phosphate and calcium phosphate.

Na₃PO₄ = 2[(3 x 23) + (31 x 1) + (16 x 4)]

             = 2[69 + 31 + 64]

             = 2[164]

             = 328 g

Ca₃(PO₄)₂ = (3 x 40) + (31 x 2) + (8 x 16)

                 = 120 + 62 + 128

                 = 310 g

2.- Use proportions to find the mass of Na₃PO₄

              328 g of Na₃PO₄ -------------------- 310 g of Ca₃(PO₄)₂

                  x                        -------------------  5 g

                  x = (5 x 328) / 310

                  x = 1640 / 310

                  x = 5.29 g of Na₃PO₄