Question #44dbb

1 Answer
Jun 28, 2015

Answer:

You can balance this double replacement reaction by inspection.

Explanation:

The unbalanced chemical equation looks like this

#Na_3PO_(4(aq)) + Ba(NO_3)_(2(aq)) -> NaNO_text(3(aq]) + Ba_3(PO_4)_(2(s))#

The easiest way to balance this equation is to treat the phosphate, #PO_4^(3-)#, and nitrate, #NO_3""^(-)#, 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.

#color(red)(2)Na_3PO_(4(aq)) + Ba(NO_3)_(2(aq)) -> NaNO_text(3(aq]) + Ba_3(PO_4)_(color(red)(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.

#color(red)(2)Na_3PO_(4(aq)) + Ba(NO_3)_(2(aq)) -> color(green)(2)NaNO_text(3(aq]) + Ba_3(PO_4)_(color(red)(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.

#color(red)(2)Na_3PO_(4(aq)) + Ba(NO_3)_(2(aq)) -> color(green)(6)NaNO_text(3(aq]) + Ba_3(PO_4)_(color(red)(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.

#color(red)(2)Na_3PO_(4(aq)) + color(blue)(3)Ba(NO_3)_(2(aq)) -> color(green)(6)NaNO_text(3(aq]) + Ba_3(PO_4)_(color(red)(2)(s))#

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