Chemistry laboratory

Question

Mixing K2SO4 and barium nitrate results in the precipitation of BaSO4. Write a balanced

chemical equation for this precipitation reaction. Include the states in your equation. What

are the spectator ion in this reaction?

Answer 1

Step 1: Write the raw (unbalanced) equation with just the individual compounds balanced for charge:

K₂SO₄ + Ba(NO₃)₂ → BaSO₄ + KNO₃

(We know Barium is Ba⁺² and we know Nitrate is NO₃^- so there needs to be two nitrates to balance the +2 charge of the Barium ion. We also know that there is Potassium (K) left that is not mentioned in the products as well as the Nitrate (NO₃) and combining them together 1 for 1 since they are a +1 and -1 charge gives us KNO₃)

Step 2: Balance the equation side to side

K₂SO₄ + Ba(NO₃)₂ → BaSO₄ + 2KNO₃

(Since there are two K's on the left, add a 2 in front of the KNO₃ on the right. That also balances the 2 NO₃'s on the left.)

Step 3: Add the states of matter.

K₂SO₄ (aq) + Ba(NO₃)₂ (aq) → BaSO₄ (ppt) + 2KNO₃ (aq)

(You are told the BaSO₄ is a precipitate. Note that you can also use "(s)" instead of "(ppt)")

Step 4: Write the total ionic equation to see what the spectator ions are:

2K⁺ (aq) + SO₄^2- (aq) + Ba²⁺ (aq) + 2NO₃^- (aq) → BaSO₄ (ppt) + 2K⁺ (aq) + 2NO₃^- (aq)

So the Potassium (2K⁺) ions and the Nitrate (2NO₃^-) ions are the spectator ions