Answer to Question #203362 in Chemistry for Mjd

Question

When 0.85mol of zinc nitrate react with 0.254mol of sodium phosphate insoluble zinc phosphate forms. Which is the limiting reactant and which is the reactant in excess?

Answer 1

Solution:

zinc nitrate = Zn(NO₃)₂

sodium phosphate = Na₃PO₄

zinc phosphate = Zn₃(PO₄)₂

Balanced chemical equation:

3Zn(NO₃)₂(aq) + 2Na₃PO₄(aq) → Zn₃(PO₄)₂(s) + 6NaNO₃(aq)

According to stoichiometry:

3 mol of Zn(NO₃)₂ reacts with 2 mol of Na₃PO₄

Thus 0.85 mol of Zn(NO₃)₂ reacts with:

(0.85 mol Zn(NO₃)₂) × (2 mol Na₃PO₄ / 3 mol Zn(NO₃)₂) = 0.57 mol Na₃PO₄

However, initially there is 0.254 mol of Na₃PO₄ (according to the task).

Thus, Na₃PO₄ acts as limiting reactant and Zn(NO₃)₂ is excess reactant.

Answer:

Na₃PO₄ is the limiting reactant.

Zn(NO₃)₂ is the reactant in excess.