Answer to Question #251269 in General Chemistry for Kyle

Question

When Calcium carbonate is made to react with phosphoric acid, it produces calcium phosphate, carbon dioxide and water.

a.) Write a balanced equation on the above reaction.

b.) Calculate for the number of grams of calcium phosphate produced from 12.5 g of calcium carbonate and 17.3 g of phosphoric acid.

c.) How many grams of calcium phosphate produced from 3.5 moles of calcium carbonate and 7 moles of phosphoric acid?

Answer 1

a) 3CaCO₃ + 2H₃PO₄ → Ca₃(PO₄)₂ + 3CO₂ + 3H₂O

b) M(CaCO₃) = 100.08 g/mol

n(CaCO₃) $= \frac{12.5}{100.08} = 0.125\;mol$

M(H₃PO₄) = 97.99 g/mol

n(H₃PO₄) $= \frac{17.3}{97.99} = 0.176 \;mol$

According to the reaction equation for two moles of H₃PO₄ we need 3 moles of CaCO₃. So, CaCO₃ is a limiting reactant.

n(Ca₃(PO₄)₂) $= \frac{1}{3} n(CaCO_3) = \frac{1}{3} \times 0.125 = 0.0416 \;mol$

M(Ca₃(PO₄)₂) = 310.18 g/mol

m(Ca₃(PO₄)₂) $= 0.0416 \times 310.18 = 12.924 \;g$

c) According to the reaction equation for two moles of H₃PO₄ we need 3 moles of CaCO₃. So, CaCO₃ is a limiting reactant.

n(Ca₃(PO₄)₂) $= \frac{1}{3} n(CaCO_3) = \frac{1}{3} \times 3.5 = 1.166 \;mol$

m(Ca₃(PO₄)₂) $= 1.166 \times 310.18 = 361.876 \;g$