Question

For the following aqueous reaction, complete and balance the molecular equation and write a net ionic equation, making sure to include the physical states of the compounds:

potassium carbonate + strontium nitrate

Answer 1

 

Step to write ionic equation equation:

1. Start with a balanced molecular equation.
2. Break all soluble strong electrolytes (compounds with (aq) beside them) into their ions
   • indicate the correct formula and charge of each ion
   • indicate the correct number of each ion
   • write (aq) after each ion
3. Bring down all compounds with (s), (l), or (g) unchanged.

(a) Step 1: Write the balanced molecular chemical equation

K₂CO₃ (aq) + Sr(NO₃)₂ (aq) -------->  2 KNO₃ (aq) + SrCO₃ (s)

Step 2: Write the complete ionic equation.

2K⁺ (aq) + CO₃^-2 (aq) + Sr⁺²(aq) + 2NO₃^- (aq)  ----------->2K⁺ (aq)   + 2NO₃^- (aq) + SrCO₃ (s)

[ Here, aqueous compounds will breaks and solid,liquid and gaseous compound will remain unchanged. So K₂CO₃ (aq)   and Sr(NO₃)₂ (aq) and 2 KNO₃ (aq)  wil breaks into ions ]

Step 3: Write the net ionic equation

[ net ionic equation is written  by crossing out the spectator ions from the complete ionic equation ]

You can recognize spectator ions by looking for ions that are present on both sides of the equation. They will always have the same exact formula, charge, and physical state.

2K⁺ (aq) + CO₃^-2 (aq) + Sr⁺²(aq) + 2NO₃^- (aq)  ----------->2K⁺ (aq)   + 2NO₃^- (aq) + SrCO₃ (s)

(B) Final net ionic equation

CO₃^-2 (aq) + Sr⁺²(aq) -----------> SrCO₃ (s)