Answer to Question #337093 in General Chemistry for Zoey

Question

What mass of solid Lanthanum (III) oxalate nonahydrate { La2 ( C2O4 )3 ∙ 9 H2O } can be obtained from 650 mL of 0.0170 M aqueous solution of LaCl3 by adding a stoichiometric amount of sodium oxalate ?​

Answer 1

n(LaCl₃) = C(LaCl₃) * V(LaCl₃) = 0.0170 M * 0.650 L = 0.011 moles

m(LaCl₃) = n(LaCl₃) * Mr(LaCl₃) = 0.011 moles * 245,26 g/mol = 2.698 g

2LaCl₃(aq) + 3Na₂C₂O₄(s) + 9H₂O(l)  →  La₂(C₂O₄)₃·9H₂O(s) + 6NaCl(aq)

m( La₂(C₂O₄)₃·9H₂O) = (m(LaCl₃) * Mr( La₂(C₂O₄)₃·9H₂O)) / 2Mr(LaCl₃)

m( La₂(C₂O₄)₃·9H₂O) = (2.698 g * 703.87 g/mol) / 2 * 245,26 g/mol = 3.87 g