Question

Analysis 1. Calculate the molar masses of the reactants, sodium phosphate dodecahydrate (12 water molecules are included), and barium chloride dihydrate. (2 water molecules are included) 2. Write the balanced equation for the reaction of the two salts (do not include the waters of hydration). 3. Calculate the molar masses for the two products. 4. Based upon your data in part B, identify the limiting reagent. Justify your answer.

Answer 1

1. Molar mass of Na₃PO₄.12 H₂O = (3*mass of Na) + Mass of P + (16 * Mass of O ) + (24*Mass of H) = (3*23)+ 31 + (16*16) + (24*1) = 380 g/mol

Molar mass of BaCl₂ . 2H₂O = Mass of Ba + (2*mass of Cl) + (4* mass of H) + (2*mass of O) = 137.33 + (2*35.453) + (4*1)+(2*16) = 244.236 g/mol

2. In balanced chemical reaction, atoms on either side of reaction are same. Thus reaction is:

2Na₃PO₄(aq) + 3 BaCl₂(aq) $\rightarrow$ Ba₃(PO₄)₂(s) + 6NaCl(aq)

3. Molar mass of Ba₃(PO₄)₂ = (3* mass of Ba) + (2* mass of P) + (8 * mass of O) = (3*137.327) + (2*31) + (8*16) = 601.981 g/mol

Molar mass of NaCl = Mass of Na + Mass of Cl = 23 + 35.453 = 58.453 g/mol