Question

Sodium phosphate and calcium chloride react to form sodium chloride and calcium phosphate. If you have 379.4 grams of calcium chloride and an excess of sodium phosphate, how much calcium phosphate can you make?

Answer 1

Answer: 353.6 g.

Explanation:

1) Word equation (given)

Sodium phosphate + calcium choride → sodium chloride + calcium phosphate

2) Balanced chemical equation

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

3) Mole ratio

2 moles Na₃PO₄ : 3 moles CaCl₂ :  6 moles NaCl : 1 mole Ca₃(PO4)₂

4)  Formula to convert grams to moles

number of moles = mass in grams / molar mass

5) Number of moles of limiting reactant

a) mass in grams = 379.4 g CaCl₂

b) molar mass CaCl₂ = 110.98 g/mol

c) number of moles CaCl₂ = 379.4 g / 110.98 g/mol = 3.419 moles

6) Theoretical yield of Ca₃(PO4)₂

    3 moles CaCl₂ / 1 mole Ca₃(PO4)₂ = 3.419 moles CaCl₂ / x ⇒

    x = 3.419 × 1 / 3 = 1.140 moles Ca₃(PO4)₂

7) Convert 1.140 moles Ca₃(PO4)₂

a) molar mass Ca₃(PO4)₂ = 310.1767 g/mol

b) mass in grams = number of moles × molar mass = 1.140 moles × 310.1767 g/mol = 353.6 g ← answer.