Question #44dbb

1 Answer
Jun 28, 2015

You can balance this double replacement reaction by inspection.

Explanation:

The unbalanced chemical equation looks like this

Na3PO4(aq)+Ba(NO3)2(aq)NaNO3(aq]+Ba3(PO4)2(s)

The easiest way to balance this equation is to treat the phosphate, PO34, and nitrate, NO3, polyatomic ions as a single unit.

So, notice that you have 2 phosphate ions on the products' side, but only one on the reactants' side. Multiply sodium phosphate by 2 to balance the phosphate ions.

2Na3PO4(aq)+Ba(NO3)2(aq)NaNO3(aq]+Ba3(PO4)2(s)

Now focus on the nitrate ions. Notice that you have 2 nitrate ions on the reactants' side, but only 1 on the products' side. Multiply sodium nitrate by 2 to balance the nitrate ions.

2Na3PO4(aq)+Ba(NO3)2(aq)2NaNO3(aq]+Ba3(PO4)2(s)

Now focus on the sodium and barium atoms. Notice that you have 6 sodium atoms on the reactants' side, but only 2 on the products' side multiply the sodium nitrate by 3 to balance the sodium atoms.

2Na3PO4(aq)+Ba(NO3)2(aq)6NaNO3(aq]+Ba3(PO4)2(s)

Now the nitrate ions are unbalanced. Multiply the barium nitrate by 3 to balance the 6 nitrate ions on the products' side with the those on the reactants' side.

2Na3PO4(aq)+3Ba(NO3)2(aq)6NaNO3(aq]+Ba3(PO4)2(s)

As it turns out, the barium atoms are balanced, 3 on the reactants' side and 3 on the products' side.